Cumbersome, colossal and deadly, they were metal robots emerging from a past everyone had believed dead: controlled by a man whose horrible mutilations in a car accident had turned him into a monster, half flesh, half machine. This is the enemy the Avengers, Steed, Purdey, and Gambit have to face when they discover that Professor Mason, Britain's leading expert on cybernetics has been forcibly abducted from one of the most heavily guarded security establishments in the country.