When Mr. Pullen comes to the office on a Saturday to finish the books for audit, he's astonished to find his employer, Sir Justin Holbrook, in the penthouse flat with a call girl. Unexpectedly, Lady Holbrook arrives and Holbrook passes the girl off as the second Mrs. Pullen. A rich Arab sheik is expected and England's entire fate depends on Holbrook signing an agreement with him, but Holbrook suddenly collapses and Pullen has to impersonate him. The arrival of the real Mrs. Pullen and others leads to an impenetrable maze of confused identities eventually resulting in Mrs. Pullen going off with the sheik and Pullen installed, presumably permanently, as Sir Justin with all that entails, including his highly attractive lady.