The Endeavor's crew is ordered to determine if the wreck of a 18th Century galleon proves that the Spanish discovered Australia before Captain Cook.

An industrial spy gets aboard the Endeavour to photograph the top secret equipment, but he turns out to be not such a bad bloke when he realises his methods endanger Captain King's life.

The Minus Five team discover a murdered man in Barrier Reef waters, and he is buried on a small, lonely island. He is to be exhumed by the police, but when Sgt. Davies goes to the grave the body is missing, and the Minus Five team land in a strange network of intrigue.