In his will, eccentric practical joker Henry Russell (Wilfrid Brambell) leaves his four relatives £150,000 each, but with stipulations designed to make each of them step completely out of character, and prove themselves as human beings. Bossy Agnes Russell (Thora Hird) must work as a maid for a month, Herbert (Ronnie Corbett) must overcome his natural shyness and rob a bank, woman chasing bachelor Simon (Leslie Philips) has to marry the first single woman he speaks to, and crime writer Denniston (Michael Hordern) is asked to commit a real life crime and be sent to jail for a month. When the four friends report back to the executor (Noel Howlett), their lives are transformed for the better. But deceased Henry still has one more surprise up his sleeve.