The Avengers S03 E10 The Grandeur That Was Rome

"Mrs Peel, We're Needed!"

Strange diseases are being reported in various parts of the world, and Steed's suspicion is that somebody has been tampering with the insecticides and fertilisers of United Foods and Dressings. Cathy Gale is captured whilst investigating, and will be the 'guinea pig' for a test on the new strain of bubonic plague.