All 12 sisters plus Mami and Wataru are ship-wreaked on an unknown island together, where they find a large and well-stocked beach house. They decide to live there while they try to figure out where they are and how to get home, and have some fun while they're at it. RinRin finds and repairs a jet ski, and they all play in the water and on the beach. Everyone is having fun, but Wataru is the only one worried about getting home. When night comes, Wataru finds out that they've actually been on Paradise Island the whole time, just on the other side from where they were living before.