Fresh from their brief adventure to colonial times, Gabe, Elizabeth, and Marty receive their next summons from Thrylos, warning them that this will be a longer adventure and to pack appropriately. Not knowing what "longer" means, the kids do as they’re told and arrive on a deserted island in 1609, just in time to see a shipwreck on the reefs!

It turns out that the ship is called the Sea Venture, and it was originally bound for the colony of Jamestown, Virginia. The deserted island is called Bermuda, reputed at the time to be surrounded by monsters. All the passengers of the Sea Venture survived the wreck, including one dog that Elizabeth happily adopts, but the ship itself did not. Gabe, Elizabeth, and Marty find themselves stranded with the would-be settlers as they build two new ships and learn to survive off the land.

Nine months later, when the kids are really starting to wonder what they’re doing there, they finally set sail in the new vessels for Jamestown - only to find that the remaining settlers there are at death’s door! The kids learn from a mysterious prophetess that a resupply ship from England is on the way. But the crew of the original Sea Venture doesn’t know this; they consider the colony a lost cause, and they are on the verge of returning to England and letting it fail. Can Gabe, Elizabeth, and Marty convince them to just hang on in Jamestown for a few more days, even when it looks like all is lost?