Four teenage girls (along with their teacher and bus driver) from Los Angeles are on a field trip in the desert. On the way to their destination their bus breaks down. While stranded they are approached by three bikers. When Jay (one of the bikers) tries to help the bus driver, the other two bikers start to harass the four girls. As soon as the teacher (Miss Tenny) observes this, she immediately defends the girls; however, she is assaulted for her interruption. After a few scuffles the group of bikers decide to help the stranded bunch and tow them to a remote cabin, with less than good intentions in store. Another altercation ensues, when Al's promise to take them to safety is now obviously broken. Almost as soon as the bus driver (Marvin) steps in, he is run over and killed by Al and his brother, Pete. To keep everyone quiet, Al and Pete hold everyone hostage in the abandoned cottage near the murder site.
