by Dennis Spooner
Twelve months ago agent Marlow, assigned to the Ministry of Agriculture, was shot whilst investigating the theft of top secret documents. His murderers, two scientists called Thornton and Carter, accidentally washed a radioactive ‘growth’ isotope down a drain. In the present, Steed, Gambit and Purdey are stirred into action after reports come in of disappearing maintenance men, vanishing vermin and seismic readings that show something huge at large in the sewers. Purdey and Gambit join forces with their Eastern counterpart Chislenko, who is also investigating the sewers. Realising that what they face is a rat mutated to gigantic proportions by the isotope, Steed concocts some bait for the creature. Meanwhile, after the rat eats Carter, Thornton shoots Chislenko and captures Purdey. Steed throws the bait onto the scientist, who is killed by the rat, which in turn is despatched by Gambit with the aid of an armour-piercing rocket launcher.
Patrick Macnee (John Steed), Gareth Hunt (Mike Gambit), Joanna Lumley (Purdey), Julian Holloway (Thornton), Peter Cellier (Carter), Jeremy Young (Chislenko), Patrick Malahide (George), Keith Marsh (Tramp Joe), Ken Wynne (Tamp Arthur), Morgan Shepherd (Walters), John Watts (Harlow), Keith Alexander (Malloy), Ronnie Laughlin (Mechanic)
Directed by Ray Austin
Produced by Albert Fennell and Brian Clemens
LWT - 21st December 1976
*Featuring John Steed, Mike Gambit and Purdey