HMS Hero is now on its way back from Hong Kong. As they move closer to Portsmouth harbour the ship's crew prepares for shore leave. Amongst preparations Mr. Parsons, the Catering Manager is busy doing the accounts totting up the takings. He retires for the night having made sure all is secure in the catering office. Later that night a break-in is reported the cash tin is found open and James Napier has to undertake and investigation. Whilst trying to learn which of the two main suspects is guilty an ulterior motive to the break-in is discovered.