GM Core
Chapter 4: Subsystems
Chases
Source GM Core pg. 214
When the PCs pursue a fleeing target—or someone is hunting them down—adding twists and turns to the pursuit builds suspense and makes the outcome more uncertain than if it were based on Speed alone. The chases subsystem helps you create cinematic scenes where the PCs must quickly overcome obstacles, from fleeing a secret laboratory set to self-destruct to desperately escaping pursuers trying to destroy an encrypted message.
The Speed rules in Player Core and vehicle rules work well for short sprints through fairly clear terrain. Over longer distances and through more complex environments, though, the path is rarely so straightforward. The chase subsystem shifts the emphasis from raw Speed to facing down the kinds of unpredictable obstacles that characters might encounter in a longer pursuit, so you can create a thrilling chase scene.
Chases are a special type of encounter. Each round, the pursued character or characters act first, then the pursuing characters act. Typically, to reduce variance, the PCs roll checks to progress while their opponents proceed at a steady pace, but if you want to emphasize the back-and-forth nature of a particular chase, you could have both sides roll instead. Characters in the same group can act in whatever order they prefer, each taking a turn. A character must act on their turn. If they pass their turn or are unable to act, they're unable to help the group and automatically cause the group to lose 1 Chase Point.
Depending on the scale of your chase, establish at the beginning how long each round lasts so the PCs understand how much they can accomplish in that time. Is it essentially a 3-action turn, or does it take minutes, hours, or days?
The Speed rules in Player Core and vehicle rules work well for short sprints through fairly clear terrain. Over longer distances and through more complex environments, though, the path is rarely so straightforward. The chase subsystem shifts the emphasis from raw Speed to facing down the kinds of unpredictable obstacles that characters might encounter in a longer pursuit, so you can create a thrilling chase scene.
Chases are a special type of encounter. Each round, the pursued character or characters act first, then the pursuing characters act. Typically, to reduce variance, the PCs roll checks to progress while their opponents proceed at a steady pace, but if you want to emphasize the back-and-forth nature of a particular chase, you could have both sides roll instead. Characters in the same group can act in whatever order they prefer, each taking a turn. A character must act on their turn. If they pass their turn or are unable to act, they're unable to help the group and automatically cause the group to lose 1 Chase Point.
Depending on the scale of your chase, establish at the beginning how long each round lasts so the PCs understand how much they can accomplish in that time. Is it essentially a 3-action turn, or does it take minutes, hours, or days?
Obstacles
Source GM Core pg. 214
During a chase, all the characters must overcome a series of obstacles that represent challenges—from security check points to quicksand—during the different legs of the pursuit. These obstacles aren't separated by specific distances; rather, the distance is narrative and can vary between obstacles as needed for the story you're telling. Travel times between obstacles can vary, too. The time scale you choose determines how PCs can act when dealing with an obstacle.
Each obstacle requires a certain number of Chase Points to overcome. Typically, half the obstacles require 1 point fewer than the number of party members, and half require 2 points fewer (with a minimum of 1 Chase Point per obstacle). Particularly challenging obstacles might require more. Typically, there are multiple ways to overcome an obstacle; for example, characters could evade a security officer or give a bribe to ignore them. Each approach usually requires a skill check or Perception check, but sometimes a saving throw, an attack roll, or something even more unusual, like casting a certain spell.
On a character's turn, they describe what they do to help the group get past the obstacle. They then attempt any required roll, or perform the required action for a choice without a check. If they attempt a roll, the result determines how many Chase Points the character gains.
If the means of bypassing the obstacle helps automatically without requiring a check—such as using a certain spell to assist—the PCs typically get 1 Chase Point. You can increase that to 2 if you feel the action is extremely helpful.
Chase Points represent the ability of the whole group to bypass the obstacle. A character who critically succeeds is able to help the other characters continue onward, while one who critically fails needs extra assistance. Players often have ideas for ways to overcome the obstacle beyond the choices you created for the obstacle. If their idea is applicable, you'll need to determine the DC and skill, or other statistic being used for that approach. This is great as long as it's creative, but be wary of a situation where a character who's legendary at a skill tries to justify how they can bypass every obstacle with that skill, such as using Acrobatics to tumble around them all, or the like. You can determine that some tactics just won't work against certain obstacles, or would help only one character without benefiting the rest and therefore aren't all that useful.
Once the PCs accumulate enough Chase Points to overcome the obstacle, they move on to the next. Extra Chase Points don't carry over to the next obstacle. However, anyone who hasn't already taken their turn that round can still take it against the new obstacle. Consequently, the characters best suited to overcoming the current obstacle might act first since the remaining characters might be better suited against the next one. The number of Chase Points the PCs have can never fall below 0.
It might help to put your obstacles in a stat block for easy reference. Inside published adventures, chase obstacles are likely to be presented in stat block form, as follows.
Chase Points 3; Overcome DC 15 Acrobatics or Athletics to weave or push through, DC 13 Society to follow the flow
Throngs of people crowd the space station corridors, making it difficult to continue the chase.
Each obstacle requires a certain number of Chase Points to overcome. Typically, half the obstacles require 1 point fewer than the number of party members, and half require 2 points fewer (with a minimum of 1 Chase Point per obstacle). Particularly challenging obstacles might require more. Typically, there are multiple ways to overcome an obstacle; for example, characters could evade a security officer or give a bribe to ignore them. Each approach usually requires a skill check or Perception check, but sometimes a saving throw, an attack roll, or something even more unusual, like casting a certain spell.
On a character's turn, they describe what they do to help the group get past the obstacle. They then attempt any required roll, or perform the required action for a choice without a check. If they attempt a roll, the result determines how many Chase Points the character gains.
Critical SuccessThe PCs gain 2 Chase Points.
SuccessThe PCs gain 1 Chase Point.
Critical FailureThe PCs lose 1 Chase Point.
Chase Points represent the ability of the whole group to bypass the obstacle. A character who critically succeeds is able to help the other characters continue onward, while one who critically fails needs extra assistance. Players often have ideas for ways to overcome the obstacle beyond the choices you created for the obstacle. If their idea is applicable, you'll need to determine the DC and skill, or other statistic being used for that approach. This is great as long as it's creative, but be wary of a situation where a character who's legendary at a skill tries to justify how they can bypass every obstacle with that skill, such as using Acrobatics to tumble around them all, or the like. You can determine that some tactics just won't work against certain obstacles, or would help only one character without benefiting the rest and therefore aren't all that useful.
Once the PCs accumulate enough Chase Points to overcome the obstacle, they move on to the next. Extra Chase Points don't carry over to the next obstacle. However, anyone who hasn't already taken their turn that round can still take it against the new obstacle. Consequently, the characters best suited to overcoming the current obstacle might act first since the remaining characters might be better suited against the next one. The number of Chase Points the PCs have can never fall below 0.
It might help to put your obstacles in a stat block for easy reference. Inside published adventures, chase obstacles are likely to be presented in stat block form, as follows.
Crowd Obstacle 1
Chase Points 3; Overcome DC 15 Acrobatics or Athletics to weave or push through, DC 13 Society to follow the flow
Throngs of people crowd the space station corridors, making it difficult to continue the chase.
Building a Chase
Source GM Core pg. 215
When building a chase, first build your obstacles, and then decide how far ahead the pursued character or characters begin and at what pace the NPCs will move. Having the NPCs clear one obstacle per round is a good rule of thumb, but it could vary depending on the situation and should especially be slower against obstacles that require more than the typical number of Chase Points to overcome.
Select or build obstacles highlighting a variety of different skills and other options so everyone in the party has a moment to shine. When choosing what skills can bypass a given obstacle, ensure a variety of approaches can work. If you've already decided that an obstacle uses Stealth, selecting Thievery as the other option doesn't really offer opportunities for different types of characters since those who are good at Thievery are very likely the same ones who are good at Stealth. On the other hand, offering Athletics as an alternative gives a soldier who's terrible at Stealth a way to help. The group can help cover for a character who's less capable at a particular obstacle, but it's more fun for players when you present substantially different options for each obstacle.
Use the following guidelines to determine how many obstacles you need for your chase. These numbers assume that the pursued party can reach a certain location to end the chase (as described in Ending Chases). If there's no such escape, you might need more obstacles.
Short: 6 obstacles, about 10–20 minutes of game time
Medium: 8 obstacles, about 15–25 minutes of game time
Long: 10 obstacles, about 20–30 minutes of game time
Select or build obstacles highlighting a variety of different skills and other options so everyone in the party has a moment to shine. When choosing what skills can bypass a given obstacle, ensure a variety of approaches can work. If you've already decided that an obstacle uses Stealth, selecting Thievery as the other option doesn't really offer opportunities for different types of characters since those who are good at Thievery are very likely the same ones who are good at Stealth. On the other hand, offering Athletics as an alternative gives a soldier who's terrible at Stealth a way to help. The group can help cover for a character who's less capable at a particular obstacle, but it's more fun for players when you present substantially different options for each obstacle.
Use the following guidelines to determine how many obstacles you need for your chase. These numbers assume that the pursued party can reach a certain location to end the chase (as described in Ending Chases). If there's no such escape, you might need more obstacles.
Short: 6 obstacles, about 10–20 minutes of game time
Medium: 8 obstacles, about 15–25 minutes of game time
Long: 10 obstacles, about 20–30 minutes of game time
Setting Obstacle DCs
Source GM Core pg. 215
When you set the DCs for an obstacle, you'll typically be using simple DCs. Use a proficiency rank that's generally appropriate for the PCs' level if you want the obstacle to be a significant obstacle. As noted earlier, you'll typically want to select a couple different ways the group can get past an obstacle. At least one check should have an easy or very easy adjustment, while the other check should have a standard or hard DC. In some cases, you might use something other than a simple DC; for example, if a specific NPC has put up a wall of steel, you would use their spell DC. This might result in some pretty tough DCs or even impassable obstacles, so use this carefully!
If a PC improvises a different way to get around an obstacle from what you planned, set the DC just like you would normally when picking a DC on the fly. Don't worry about adjusting the DC to be easy or very easy because the PC is likely to be good at the skill they've chosen.
If a PC improvises a different way to get around an obstacle from what you planned, set the DC just like you would normally when picking a DC on the fly. Don't worry about adjusting the DC to be easy or very easy because the PC is likely to be good at the skill they've chosen.
Shortcuts and Split Paths
Source GM Core pg. 215
You might want to build a chase with multiple paths that split and rejoin so you can have a shortcut (with easier DCs or fewer obstacles) or paths that appeal to different types of characters. For instance, one obstacle might allow a PC who critically succeeds at a Perception check to find a faster path through an air duct, without the obstacles of navigating a busy nightclub. This can be fun, but it can also split up the group. Familiarize yourself with the Solo Chases sidebar to make similar adjustments for a divided group.
Ending Chases
Source GM Core pg. 215
Once you have the obstacles, decide the end conditions. Chases often end when the pursuer reaches the same obstacle as the pursued, leading to a combat encounter or other scene. However, it's less clear when to end a chase otherwise. It's typically best to have an obstacle that ends the chase with the pursued character getting away, as long as they overcome the obstacle before being captured. This is usually better than ending the chase after a certain number of rounds because reaching a hideaway makes more narrative sense and because you might not be able to predict how far the pursued characters move in those rounds, making you run out of obstacles. You can also end the chase in favor of the pursued characters if they ever get a certain number of obstacles ahead of the pursuers (typically three), as the pursuers simply lose the trail. You should still have an end point to the chase, though, in case that never happens.
Types of Chases
Source GM Core pg. 215
- Chase Down: The PCs pursue adversaries. The PCs go second in initiative since they're the pursuers. Start the enemies one obstacle ahead of the PCs (or at the same location for a short chase), and end the chase if the PCs catch up to the enemies, or if the enemies reach a certain location that represents their safety or escape.
- Run Away: The PCs attempt to escape. They'll go first in initiative since they're being pursued. It's usually best to start them one obstacle ahead of their foes and end the chase if they reach a certain location or are three obstacles ahead of the foes at the end of a round.
- Beat the Clock: The PCs try to get through all the obstacles before a certain number of rounds pass, such as if the PCs are trying to outrun a natural disaster or race in a timed challenge. The number of obstacles should usually equal the number of rounds.
- Competitive Chase: The PCs and their adversaries are both chasing the same thing or trying to reach the same location, and whoever gets there first wins. This works like chase down, except that either party could win. Because there's more than one set of pursuers, you might have the PCs and their competitors roll initiative to see who goes first each round (while still moving all NPCs at a steady rate).
Running a Chase
Source GM Core pg. 216
When running a chase, narrate the scene and give vivid descriptions of the obstacles the PCs face, rather than just reading off a list of skills and immediately having the players start rolling dice and attempting checks. A chase is a framework for roleplaying, not just a dice game. Encourage the PCs to describe what they're doing and how they're helping their comrades overcome each obstacle.
Typically, it's best to tell the players the DCs of the default options, so they can make informed decisions. At the very least, you should indicate the relative difficulty of the clear paths.
Try to make it feel like the PCs are really part of a chase scene, like in a movie. As each side makes progress, describe how they pull ahead or close the gap. PCs far from their foes might hear shouts in the distance. As they get closer, they catch glimpses, and then finally see their quarry in full view once they're on the enemies' heels. Think about how the events of the chase affect the environment as well. For instance, if a colossus is chasing after the PCs, after the PCs overcome an obstacle consisting of a cluttered construction site, you could describe how the colossus flattens the structure beneath its feet as it stomps after them.
Typically, it's best to tell the players the DCs of the default options, so they can make informed decisions. At the very least, you should indicate the relative difficulty of the clear paths.
Try to make it feel like the PCs are really part of a chase scene, like in a movie. As each side makes progress, describe how they pull ahead or close the gap. PCs far from their foes might hear shouts in the distance. As they get closer, they catch glimpses, and then finally see their quarry in full view once they're on the enemies' heels. Think about how the events of the chase affect the environment as well. For instance, if a colossus is chasing after the PCs, after the PCs overcome an obstacle consisting of a cluttered construction site, you could describe how the colossus flattens the structure beneath its feet as it stomps after them.
Visual Aids
Source GM Core pg. 216
It can help your players visualize the chase to use a series of cards or a rough map (such as a large-scale city map rather than a 5-foot grid) to show locations. Use one miniature or token to represent each side of the chase. You might place cards with obstacle names on them face down, revealing them as PCs reach them, and letting a PC peek at an upcoming card if they scout it from a distance.
If the PCs get Stuck
Source GM Core pg. 216
Sometimes, despite their best efforts, an obstacle will stymie the PCs over and over again. In most cases, after 3 rounds of the PCs struggling with an obstacle that requires the standard number of Chase Points, it's a good idea to just say they found another way around it. If presenting another way around the obstacle just doesn't make sense, such as if the PCs can't hot-wire an abandoned vehicle, you might introduce an NPC or other outside force that can help them bypass it, but at a high cost.
Sample Obstacles
Source GM Core pg. 217
You can use the following obstacles in your chases, which are organized by environment. The name is followed by the level of group they're best suited for, and many include both a basic version for lower levels and a higher-level version.
Underground Obstacles
| Crumbling Corridor (1st) | DC 13 Acrobatics to avoid damaging the walls, DC 15 Crafting to repair the walls; Quaking Corridor (11th) DC 25 Acrobatics, DC 30 Crafting |
|---|---|
| Fungal Grotto (1st) | DC 15 Fortitude to endure poisonous spores, DC 13 Survival to avoid fruiting bodies; Virulent Fungi (5th) DC 20 Fortitude, DC 18 Survival |
| Collapsed Tunnel (5th) | DC 20 Athletics to dig through, DC 18 Perception to find another path; Ancient Collapse (12th) DC 30 Athletics, DC 28 Perception |
| Mining Drill (5th) | DC 20 Reflex to dodge the drill, DC 15 Thievery to disable the drill; Fleet of Drills (12th) DC 30 Reflex, DC 28 Thievery |
Urban Obstacles
| Chain Link Fence (1st) | DC 13 Athletics to climb, DC 15 Thievery to unlock the gate; High Welded Wire Fence (8th) DC 20 Athletics, DC 25 Thievery |
|---|---|
| Crowd (1st) | DC 15 Acrobatics or Athletics to weave or push through, DC 13 Society to follow the flow; Convention Crowd (4th) DC 20 Athletics, DC 18 Society |
| Illegally Parked Vehicle (1st) | DC 13 Crafting or Piloting to cut the brakes, DC 15 Intimidation to make the owner move it; Food Truck (5th) DC 20 Crafting or Piloting, DC 22 Intimidation |
| Rickety Fire Escape (1st) | DC 15 Acrobatics to slide down, DC 13 Athletics to swing from landing to landing; Crumbling, Steep Fire Escape (5th) DC 18 Acrobatics, DC 20 Athletics |
| Security Drone (1st) | DC 14 Computers to reprogram, DC 16 Stealth to sneak past; Security Robot (9th) DC 26 Computers, DC 28 Stealth |
| Viral Flash Mob (2nd) | DC 15 Performance to join in, DC 13 Thievery to disable the sound system; Viral Surprise Concert (12th) DC 30 Performance, DC 28 Thievery |
Vehicle Obstacles
| Confusing Side Streets (1st) | DC 13 Society to recall the street layout, DC 15 Survival to navigate through the tangle; Twisting Back Alleys (5th) DC 18 Society, DC 20 Survival |
|---|---|
| Demonstration (1st) | DC 15 Intimidation to part the crowd, DC 13 Performance to sway the masses; Parade (5th) DC 20 Intimidation, DC 18 Performance |
| Red Light (1st) | DC 13 Computers to hack the lights, DC 15 Piloting to drive through oncoming traffic; Busy Red Light (11th) DC 25 Computers, DC 30 Piloting |
| Spiked Rail (1st) | DC 15 Athletics or Crafting to create an improvised ramp, DC 13 Perception to find a way around; Blockaded Street (5th) DC 20 Athletics or Crafting, DC 18 Perception |
| Traffic Jam (1st) | DC 13 Perception to spot an opening, DC 15 Piloting to swerve through traffic; Rush Hour (5th) DC 18 Perception, DC 20 Piloting |
| Construction Site (2nd) | DC 17 Piloting to swerve through the site, DC 13 Society to understand the site's organization and layout; Demolition Site (5th) DC 20 Piloting, DC 18 Society |
Wilderness Obstacles
| Deep Mud (1st) | DC 15 Athletics to slog through, DC 13 Perception to find a path; Horrid Bog (5th) DC 20 Athletics, DC 18 Perception |
|---|---|
| Downpour (1st) | DC 13 Fortitude to push through, DC 15 Nature to predict the weather; Magical Thunderstorm (11th) DC 25 Fortitude, DC 30 Nature |
| Rope Bridge (1st) | DC 15 Acrobatics to cross carefully, DC 13 Crafting to make repairs; Solitary Frayed Rope (11th) DC 30 Acrobatics, DC 25 Crafting |
| Rushing River (1st) | DC 15 Athletics to swim or hop across stones, DC 13 Survival to find a ford nearby; Flash Flood (5th) DC 20 Athletics, DC 18 Survival |
| Tangled Forest (2nd) | DC 17 Perception to find the way, DC 13 Survival to plot a path; Enchanted Forest (5th) DC 20 Perception, DC 18 Survival |