The Doctor; Gus Goodman (death); Josiah W. Dogbolter; Hob; Wrekka; The Gaunts; The Moderator (death)
Synopsis
The Doctor and Gus find themselves in the midst of a labor dispute on a mining planet. When they are taken before the owner of the mining company, Dogbolter, the Doctor reveals that they are time travelers to save Gus's life. The Doctor refuses Dogbolter's offer to buy the TARDIS just before he and Gus escape. Dogbolter then hires the Moderator to track down the TARDIS. He succeeds just as the Doctor returns Gus to his home world and native time. Gus dies in the ensuing shootout, and the Doctor drops the wounded Moderator off in a hospital.
The troops at U.N.I.T. Skywatch-7 track a possible meteorite landing. When the soldier who goes out to check returns, he is acting strangely. When his colleagues attempt to pursue they discover that he has been replaced by a Zygon.