The unexpected adventures of children on a school cruise to Portugal and North Africa. In Tangier, Steve, whose hobby is detecting, suspects that a parcel carried by another boy is contraband. Steve and his pals get into trouble trying to get hold of the parcel, but, in the process they uncover and foil the plans of a passenger to smuggle a stolen painting back to England.

Victorian schoolboy adventure. Freddie is sent away to a boarding school where he is very miserable and tries to escape in several instances. Finally the head of the school who made his life impossible is accused and taken away.