Still marooned in the cottage, the Doctor takes Mike Yates back in time to the 1930s for his next lesson about the infestation of the alien swarm...
Part of a five-story adventure written by Paul Magrs.
Starring Tom Baker as the Fourth Doctor, Richard Franklin as Mike Yates, Susan Jameson as Mrs Wibbsey, Claire Corbett as Ernestina Stott and Christian Rodska as the Reverend Small.
Producer: Kate Thomas
Made by BBC Audio.