At Burnham Preparatory School for boys, senior Dan Bartlett fails his mid-term exam in chemistry and must take a make-up test, which means he cannot go to the Caribbean with his girl friend, Lori Cronenberg, and her family. Dan has Lori tell her family that he has the stomach flu, arousing much sympathy from her parents, Bill and Buffy. However, Dan’s roommate accidently lets slip that Dan must stay behind because he failed the exam, confirming Bill Cronenberg’s opinion that Dan is not worthy of his daughter. Dan’s chemistry teacher, Mr. Kowalski, stops by Dan’s room, to ask how he could do so poorly on the exam. Feeling sorry for Dan missing his trip, Kowalski gives Dan one more question to answer. When Dan is able to recite the chemical formula for caffeine, Kowalski passes him. Dan takes a taxi to the airport, but the Rosenberg’s flight has already taken off. He books another flight and soon is in Porta Rosa. He telephones the Marina Shores resort with a message for Lori that he will see her soon. Unable to get a taxi to the resort, Dan gets a ride with three locals, Cleon, Alphonso, and Roxanne. When they see a police roadblock ahead, they take a detour through the woods because they have marijuana in the car. However, they accidently run the car off the path into a river and cannot get it unstuck. The others are content to smoke marijuana and camp out until morning, but Dan tries his best to get the car out of the water, to no avail. When the sun comes up, Dan starts walking through the woods, but the others get the car towed out of the water. When he finally makes it to the Marina Shores resort, Dan finds the clerk did not deliver his message to Lori and learns the Cronenberg family has checked out, deciding to rent a yacht. By the time Dan gets to the marina, the yacht, the Crystal Slipper, has already set sail. On the yacht, Captain Andrew and his first mate, Chris Honeywell, show the family around. Chris, who just joined the crew, flirts with Lori, who rejects him. On shore, Dan goes to a bar to drink his sorrows away and meets “Mac” MacClaren, who is looking for the first mate of the Crystal Slipper. Dan drinks so much rum that he passes out and awakens the next morning on Mac’s sailboat, Albatross. Mac lies, saying that Dan insisted on coming aboard the ship so he could get to his girl. Mac reports that if the weather holds up, they should catch up to the Crystal Slipper in a day. The next morning, Dan spots the yacht in the distance, while Lori, on board the Crystal Slipper using binoculars, thinks she sees Dan on the sailboat behind them. However, storm clouds move in and soon both boats are in the middle of a hurricane. When Mac is thrown overboard, Dan jumps in to save him. With Mac in no condition to pilot the boat, Dan steers it through the pounding waves and torrential winds. The next morning when the storm has passed, the engine on the Albatross blows up. Convinced Mac is somehow trying to keep him on the boat, Dan jumps overboard and swims to shore, where he is immediately arrested and thrown in jail. Dan is unclear about the charges against him since he does not speak Spanish, but tries to bribe the police officer. The officer confiscates Dan’s wallet and leaves him in jail. The next day, Mac comes to the jail and throws a bomb inside. The wall collapses and all the prisoners escape. Mac drives Dan away in a jeep, but police give chase. Mac drives the jeep into a field to hide, then tells Dan to hike to the airport while the police chase Mac in the jeep. Dan makes it to the airport and gets the last seat on a small airplane. Once in the air, the stewardess has the passengers vote on their destination. The majority choose to go to Vista del Lago rather than Laguna del Mar, where Dan wants to go. However, when someone tries to hijack the plane, Dan stops him. Grateful, the passengers agree to fly to Laguna del Mar. Meanwhile, the Cronenbergs arrive safely in Laguna del Mar, leave the yacht and check into a hotel, where they meet Victor Honeywell, a businessman from Dallas, and his young girlfriend, Carmalina. However, when Lori takes a rowboat back to the Crystal Slipper, she finds Captain Andrew dead. When she returns to shore to tell her parents, she finds Victor Honeywell and his son, Chris, the first mate, holding her family hostage in their hotel room. After the plane lands, Dan rides a bicycle to the hotel and sees the yacht anchored in the lagoon. He takes a rowboat to the yacht, where he finds Chris and others searching the boat. Dan hides in a closet and discovers Captain Andrew’s dead body. He steals Chris’s gun, then locks Chris in the boat’s fish locker. He radios for help, then goes ashore. Dan rescues Lori, then throws a grenade onto the beach to distract Victor Honeywell and his men. He rescues the rest of the Cronenbergs, and they drive off in a jeep, with Victor’s men following close behind. Dan drives the jeep into a field to hide, then after Victor passes, comes up behind and rams into Victor’s truck, pushing it over a cliff into the ocean. Police arrive at the Crystal Slipper and arrest Victor’s men. The next day, Bill Cronenberg announces that Dan is now part of the family. He charters a sailboat for Dan and Lori, telling them to meet up with the family in Cabo San Lucas in a few days. Bill also hires Mac MacClaren to skipper the boat. But once underway, Mac jumps off and swims back to shore, saying Dan knows how to skipper a boat just fine. Dan and Lori kiss and sail into the sunset.