The kids' plan to go to the island is thrown into disarray when a message is found from Mr. Taylor warning the kids not to come. After deciding to risk the voyage, the kids arrive at the island but discover only more questions.
When Ryan's father goes to investigate a scientific research facility based on an off-shore island, he finds himself stranded with a group of strangers. When nobody returns from the island, Ryan receives a cryptic message from his dad.
Josh dumps Ryan in the middle of the mysterious forbidden zone to pay him back for cutting off their communications. Shocked by his actions, the girls insist on rescuing him.
The kids force Rob to leave camp, but it comes back to haunt them when they discover he holds the key to Zuke's health. Gabe is invited to stay at camp, Elly plays miracle worker, and Rob has an unlikely defender.
Stranded at the medical outpost on the quarantine island, Ryan and Jarrah repair their boat and decide to return home. Meanwhile, much to Lily's disgust, Josh and Rob initiate a hunt to track down the intruder.