On his doctor's orders Poirot has gone to stay in the seaside resort of Brighton, where he is frequently mistaken for Lucky Len, who gives out money on behalf of a newspaper to people who recognize him. Poirot is staying at the Metropolitan hotel, as are Mr. Opalsen, a theatrical producer, and his wife who is an actress starring in a play at a local theatre. A set of valuable pearls which Mrs. Opalsen wears in the play is stolen from her room, and suspicion falls on her maid Celestine, who was in the room next door. Celestine loves Andrew, the impoverished young author of Mrs. Opalsen's play but they cannot afford to get married and she is accused of taking the jewels to finance their marriage. Poirot solves the case and unmasks the real culprit, being rewarded by Opalsen and getting a bonus when he identifies the real Lucky Len.