City at World's End by Christopher Bulis

City at World's End is a novel in the First Doctor series as they visit Arkhaven, the last bastion of civilisation on a doomed world.

The Cities inhabitants are hoping that a final desperate gamble will save their lives. Not everyone is working toward the common goal though, there are some factions planning to be in charge of shaping the new world.

As the countdown to doomsday fast approaches, the Doctor must discover the true enemy, before everything is destroyed.