George Thomason and Ken Pile are gangsters in London. Ken loves animals and he has a stutter. They plan to steal a jewels. They ask two Americans for help: con artist Wanda Gershwitz and weapons expert Otto West. Otto is a stupid and mean. Also, he does not like British people. Wanda and Otto are lovers. They hide this from George and Ken by pretending to be siblings. This frees Wanda to work her charms on them.