Doctor Who City at World's End by Christopher Bulis

This compilation of excerpts details the desperate situation in the city of Arkhaven as its moon threatens to collide with the planet Sarath. Following a meteor strike that damages their time machine and separates one of their companions, the Doctor and Ian Chesterton are forced to interact with the city's inhabitants, including the pragmatic Mayor Draad, the rigid Bishop Fostel, and a group of outcast Non-Citizens (NC2s) led by Gelvert. Simultaneously, Barbara, the missing companion, navigates the city's underground tunnels after surviving the tower collapse. The city's plan for survival centers around a massive Ship, initially believed to be an evacuation vessel for all, but it is revealed that only a select few are intended to escape to the planet Mirath, while the NC2s are to be abandoned or worse. Further complicating matters, the Doctor's other companion, Susan, is kidnapped by Fostel's followers due to her alien nature and perceived threat to the Church's authority. The text culminates with the revelation that the Ship is in fact the Lander module of a larger, failed project, controlled by the city's artificial intelligence, Monitor, who has his own agenda for survival, and the unexpected arrival of the Taklarians, believed to be defeated, who also seek to take the Lander for themselves, leading to a final confrontation for the desperate survivors.