Hancock bumps his head and suffers from temporary amnesia. Whilst he is unable to remember who he is, Sid persuades Hancock that he is Prince Nicolai, the last heir to the Russian Royal Family's fortune... but there are others making the same claim.

Hancock is worried by his new neighbour who seems to keep bringing in bodies and dumping them in an incinerator in the back garden. Hancock decides to investigate.

Sid has set up an amusement arcade, but when Hancock finds out he leads a campaign to have it closed down. Meanwhile, Hancock seeks election to the Council but when Sid's arcade is closed down he moves it to Hancock's house.

Hancock takes on a new job as an air steward. But one of the passengers on his first flight is Sid who is on the run from the police, and the other passengers include four police officers looking for a bank robber.

Hancock becomes a lawyer but when he defends an obviously guilty Sid James in court he finds himself the subject of a guilty verdict.