An alternate timeline for TimeLords.
From the back cover:
"Avengers. 2212 AD.
A small team of probability researcchers watches helplessly while a temporal ambush wipes out 99% of Earth's population. In the only surviving orbital colony, they become Avengers, to protect and rebuild, and to find and destroy the organization known only as Black Death.
A generation later, the fight goes on. Earth is still a ravaged wasteland, but the tiny reconstruction teams are making a difference. Black Death is still out there, but has grown more subtle. Avenger agents must journey to alternate worlds to stop threats aimed at their own, or journey into Earth's wastelands to stop long-term plots.
Avengers contains complete backgrounds on this alternate timeline, plans of the space colony Chronos, new equipment, character generation, and the short adventure, Fall of Parugue, suitable for Avenger agents or introductory SpaceTime characters.