Two recent high school graduates, Tracy and Gene, drive their beat up van to Stony Lake for one last adventure before college. On the way they spot Bee and Sparky, two teenage girls, hitchhiking. Gene invites the girls to spend the night in the boys' tent, while Tracy makes out with Sparky in the back seat. The foursome comes upon a stranded biker in need of gas, fill his tank, and he speeds off. Later, they stop at a country store. While the girls shoplift food, Gene flirts with an attractive older woman who informs him she has a cabin at the lake, but before Gene can get her name, she drives off. That night, the couples make love, but the next morning, the boys wake alone. They check the girls’ bags to discover Tracy’s camera and Gene’s radio. The boys reclaim their possessions. The girls drive up with new boys, retrieve their bags and leave. The boys laugh until they discover that Gene’s watch is missing. Later in the day, the boys stop to fix a flat tire and hear flute music coming from a meadow. Upon investigation, they discover a young male hippie, Roger, and two topless young women, Deborah and Liza, frolicking in the grass. Roger offers the boys his women, then plays the flute while the couples make love. Soon, Roger and the girls consume all the food and beer, then commandeer the tent. Roger announces his plans for the group to drive south in the morning. In the middle of the night, Gene hears someone outside the tent, opens the flaps and sees the motorcyclist they helped earlier. Without a word, the man leaps on his motorcycle and leaves. The next morning, as the hippies sleep off their drunken stupor, Gene and Tracy take the tent down around them, and sneak off in the van. They stop at a nearby diner and meet Fred, a local man, who offers to introduce the boys to a nymphomaniac in exchange for a few cases of beer. The boys agree, unaware they are being watched by three men. That night, Fred takes the boys and the beer to a garage behind a rundown home, where they meet Regina, a middle-aged alcoholic, who makes love to Fred. As Gene and Tracy wait their turn, the three men from the diner arrive and make the boys leave at knifepoint. Deciding to get even, Gene knocks on the door to the house and when a tough looking man answers, Gene tells him to call the police about four men dragging a woman into the garage. The man is Regina’s husband, and instead of calling the police, he grabs a shotgun, goes into the garage and starts shooting. All four men run out with their pants around their knees as the boys speed off in the van. The next day, the boys reach the lake and make camp, only to have the motorcyclist appear again. The biker says he does not need any help, so the boys ask him to ride somewhere else and he drives away. Tracy searches for the older woman he flirted with at the grocery store, finds her cabin and they make love. Later, as the woman feeds Tracy lunch, her grownup son arrives and Tracy leaves. Meanwhile, Gene swims in the lake, and is startled when a woman surfaces in front of him. She does not give him any information, but orders him to meet her at four, and swims off. Later, the girl finds Gene on the beach and makes love to him. Still refusing to give any information about herself, she hikes off. That night, as Gene and Tracy sit in their tent, the three men from the diner arrive seeking vengeance. They thrash the boys until the motorcyclist appears, beats the men bloody and chases them off. Without waiting for thanks, the motorcyclist gets on his bike and rides away. The next day, the boys drink beer as they drive home and toast to the summer, then to college and freedom.