The launch with Lieut. Hope and Cleo Burke drifts unto daylight, when a landing is made on Santa Cruz island. Olga Ivanhoff, the Russian spy and Gerald Morton, who fears Cleo will inherit his uncle's estate, float ashore on the island after a night of terror. Hook Barnacle, Hope's friend, comes ashore on the locker, Mahlin and Satsuma, also seeking the submarine secret, reach the island in a boat they have stolen from the lighthouse keeper. Mahlin sees Hope hastening to Fitzmaurice's cabin. Hope in turn discovers Mahlin on the same mission. A race starts between Mahlin and Hope to see who first will reach the cabin. Olga and Morton are witnesses to this race. They also attempt to reach the cabin in advance of the others. Fitzmaurice leaves the treasured volume in his cabin first and runs out with the book just as Hope arrives. Hope pursues Satsuma. Satsuma runs to a sheer cliff. He and Hope fight a revolver duel, each being hidden behind rocks. Satsuma exhausts his ammunition in a desperate attempt. to escape with the book, he jumps over the cliff into the ocean. Hope runs down to his launch. Satsuma almost successful in his hazardous method of escape until he is pursued by a shark. He puts the book on a piece of wreckage and starts out for shore. Hope gets the book. Returning to the landing place the propeller of Hope's launch is damaged by seaweed. Hope and Cleo arrange to remain all night with Fitzmaurice, so that Hope can make repairs to his launch the following day. Hook is to sleep in the launch. Mahlin and Satsuma steal dynamite from a construction camp and plant it under Fitzmaurice's cabin. Satsuma lights the fuse and peers into the window. Cleo sees him. She creams in fright. The cabin is blown up, the heavy walls falling over the cliff to the jagged rocks below. How do Lieut. Hope and Cleo Burke escape death? - Moving Picture World, July 8, 1916
See Episode One for cast listing.