The Assassination Bureau is loosely based on a turn-of-the-century yarn written by Jack London. Nellie Bly-style girl reporter Sonya Winter (Diana Rigg) tries to get the goods on shady businessman Ivan Dragomiloff (Oliver Reed). Ivan is in charge of a wide-reaching organization which, for a price, assassinates those who "need killing." As a challenge, Sonya offers to pay Ivan a huge sum if he'll instruct his minions to assassinate him; Ivan agrees, hoping that it will put a little kick in his work. Despite his profession, Ivan isn't the villain of the piece; that honor goes to evil nobleman Lord Bostwick (Telly Savalas), whose perfidy leads Sonya into joining forces with the Assassination Bureau. A wild climactic chase in a zeppelin caps this tongue-in-cheek escapade.