Professor Langdon St. Ives brilliant but eccentric scientist and explorer is at home in Aylesford with his family. Not far away a steam launch is taken by pirates, the crew murdered, and a grave is possibly robbed of the skull. The suspected grave robber, the infamous Dr. Ignacio Narbondo, is an old nemesis of St. Ives. When Narbondo kidnaps his son Eddie, St. Ives races into London in pursuit.