Now that twins Clive and Eric are back on dry land, it seems their days of excitement and...er...misadventure are well and truly behind them. Until their dad lands a job as manager of a swanky London hotel and Grandma and Grandad don't seem too keen on the idea of looking after the twins while he's away. Strange that. Anyway, off they all go, to live the life of riley in the hotel's penthouse suite. But it isn't long before something goes wrong. This time, missing jewellery from the hotel safe. And guess who the prime suspect is? Dad. The twins know he is innocent, but the evidence against him is mounting and things don't look good. In another display of courage and daring, albeit cack-handed and ill-thought out, the boys set out to prove that their Dad is not guilty, getting into a whole lot of trouble in the process...of course.