Ever since his adventure in the center of the Earth, Sean Anderson has been looking for other places mentioned by Verne and other Vernians. He is notified about a coded message, and breaks into a satellite facility to fully receive it. With the help from his stepfather Hank (Dwayne Johnson) he decodes the message leading him to find the map that leads him to Verne's mysterious island. Along with Gabato and Kailani, Sean embarks on a mission to find his grandfather, the legendary Vernian Alexander. But unexpected problems arise as Alexander made a mistake that could change everything.