Undeath of History: Mechanics of Time Travel

We return again to my TimeWatch setting, the Undeath of History. This was originally be a discussion of the Patchworks, the intertemporal set of ruins that allows access to all times and many doomed versions of Earth. But I ran behind and the mechanics of time travel in this setting alone is enough to fill a column. So here we are.

The Mechanics of Time Travel

The Setup

First the basics. By entering into the Patchworks, a traveller can travel back and forth in time. Traversing the Patchworks takes some time (often hours, sometimes minutes or days) but with the right know how you can arrive almost anywhen (surviving is another story).

Changing history (or an alternate history) isn’t difficult in most cases. One life in the flow of time is an invisible ripple in a raging river. Large scale changes (like saving a world) however are much much harder. The timeline resists changes that work against the downward pull of the future. Only careful and sustained effort can alter that dark destiny.

In rare instances the timeline can branch (usually when major temporal disaster occurs). New (and often equally doomed) histories instantly appear.

Paradoxes in this setting can occur but have no additional effect on the timeline. Murdering your past self, making objects with closed timelines, and other head scratchers just work. The consequences for the traveler however are severe. They risk dislocation from the stream of time (and the source of vitality in the world) and becoming one of the Undead.

Rules

Entrance: entering the Patchworks is an investigative use of the Patchworks, Architecture or Occult Studies abilities. The traveller picks out the right spot in the local architecture, waits for the shadows to fall just right and then pass through into the ruins between history. Typically this does not need a spend unless there is some time pressure or otherwise complicating circumstance. For example, it may cost a point of the relevant skill to find an entrance before the radioactive mutants find you or within the windswept (and structure-less) plains of prehuman Siberia.

The Chill Winds of History: entering the Patchworks immediately inflicts 2 points of damage to Temporal Stability. This amount may be higher if the traveler is entering from a particularly distant period. Entering the Patchworks from a doomed alternate timeline imposes a Temporal Stability test Difficulty 4 (5 if right at the apocalypse). Failure inflicts 3 points of Temporal Stability. Add additional difficulty if the time period exists post- or pre-human.

Time spent within the Patchworks can also be dangerous. Each day exposed to the temporal winds (which is everywhere outside of certain protected regions like the Bone Market, the Last Citadel, or the Necropolis) imposes the risk of losing Temporal Stability. The Difficulty for this test is 3 and inflicts 2 Temporal Stability.

If camping down for a long period (where the PCs can be recovering general pools regularly) just have the PCs roll a Difficulty 5 check (+1 for a week, +2 for a month, +3 for a year, and so on) to see if they suffer any significant loss. If they fail they lose 5 Temporal Stability upon the beginning of the next scene.

Exit: Finding the right exit from the Patchworks uses the same skills as Entering with the same spend requirement (i.e. no cost unless the user is under time pressure or wishes to exit at a very specific time and/or place). Exiting the Patchworks has no negative effect on Temporal Stability.

Otherwise the normal rules for paradoxes apply. Within the Patchworks all Temporal Stability checks are at +1 difficulty (accounted for above). Also most time travelers in this setting will be outside of their home timeline frequently and suffer the same increased difficulty.