Chapter 1

After the events of "Up, Up, and Away", the Doctor and her companions have been laying low in Sheffield. While waiting for Captain Jack to wake up, the team makes a startling discovery about one of their own members. To confuse the situation, Team TARDIS can't be sure who to trust; a swarm of Doppelgängers seem to have made their way into the city, replacing its inhabitants. Who is who, and where are the originals?