On the weekend leading up to April Fools' Day, a group of college friends, consisting of Harvey, Nikki, Rob, Skip, Nan, Chaz, Kit, and Arch, gather to celebrate spring break by spending the weekend at the island mansion of Skip's cousin, Vassar student Muffy St. John. As Muffy prepares details around the house, she finds an old jack-in-the-box and recalls receiving the toy at a childhood birthday party. Her friends, meanwhile, joke around on the pier while awaiting the ferry. En route to the island, as their antics become more boisterous, local deckhand Buck is seriously injured in a gruesome accident.