Sean Anderson accompanies his new stepfather, Hank, to find his grandfather, Alexander, who went missing while exploring a lost island.

• Dwayne Johnson as Hank Parsons, Sean's stepfather.
• Josh Hutcherson as Sean Anderson
• Vanessa Hudgens as Kailani, Sean's love interest and a tour guide.
• Michael Caine as Alexander Anderson, Sean's grandfather.
• Luis Guzmán as Gabato, part of a father-daughter tour guide team.
• Kristin Davis as Elizabeth "Liz" Anderson, Sean's mother.