When the TARDIS malfunctions and the doors open in the time vortex, the travellers and their Ship shrink to the size of insects. When they arrive on Earth, they uncover a murderous plot involving a new insecticide - but how can they stop the crime in their miniaturised condition ? (Originally broadcast in three parts.)
Quest roles:
William Russell(Ian Chesterton), Jacqueline Hill(Lexa), Carole Ann Ford(Susan Foreman)