Bowen Tyler’s fabulous adventure began with a terror-haunted trip as a captive in an enemy submarine-only to end on the rocky shores of a monster-ridden lost world where time had stopped. Thus begins one of the most thrilling Science Fiction series that the creator of Barsoom and Tarzan ever conceived-the epic of the lost continent of Caprona and of the American who first set foot there.

A manuscript is recovered from a thermos off the coast of Greenland purporting to be the journal of Bowen J. Tyler, an American passenger on a ship sunk in the English Channel by the U-33, a German U-boat, in World War I 1916. He is rescued by a British tugboat with a female survivor, Lys La Rue. The tug is also sunk, but its crew manages to capture the German submarine after it surfaces. Unfortunately, the remaining British craft continue to regard the sub as an enemy, and they are unable to bring it to port. Sabotage to the navigation equipment sends the U-33 astray into the South Atlantic. The imprisoned German crew retakes the sub and begins a raiding cruise, only to be overcome again by the British. A saboteur continues to guide the sub off course, and by the time he is discovered, the U-boat is in Antarctic waters. The U-33 is low on fuel, with its provisions poisoned by the saboteur Bensen. A large island ringed by cliffs is discovered and identified as Caprona. A freshwater current guides the U-boat to a stream issuing from a subterranean passage, which they enter with the hope of replenishing the water supply. The U-boat surfaces into a tropical river teeming with primitive creatures extinct elsewhere. Attacked, it submerges again and travels upstream in search of a safe harbor. It enters a thermal inland sea, essentially a huge crater lake, whose heat sustains Caprona’s tropical climate. As the sub travels north along the island’s waterways the climate moderates and wildlife undergoes an apparent evolutionary progression. On the shore of the lake the crew builds a palisaded base, dubbed Fort Dinosaur for the area’s prehistoric reptiles & fauna. The British and Germans agree to work together under Tyler, with Bradley, the mate from the tug, as second in command and Von Schoenvorts, the original sub commander, in control of the Germans. The castaways are attacked by horde of primitive beast men and take prisoner Ahm, a Neanderthal. They learn that the native name for the island is Caspak. Oil is discovered, which they hope to refine into fuel for the U-33. As they set up operations, Bradley undertakes various explorations. During his absence Lys disappears and the Germans mutiny again, absconding with the submarine.

Tyler leaves the other survivors to find and ultimately rescue his British love interest. Reunited and stranded in a LAND THAT TIME FORGOT…