Max Wheeler

 was a radio star. He became worried when his audience started disappearing one by one. He met Susan and the First Doctor, who were stuck in London because something was interfering with the TARDIS.

Max had served in World War II, and it turned out that an alien race that was used during the war were now causing both problems. Max and his ex-wife Maxine helped the Doctor and Susan defeat the aliens. (PROSE: Losing the Audience)