Andrzej and Krystyna are a married couple driving to the marina to spend a Sunday sailing. On their way, a hitchhiking student causes them to veer off the road. Andrzej confronts the lad, who only wants a ride. They give him a lift to the pier and then, surprisingly, invite him onboard. All three then embark for a leisurely sail along a beautiful, isolated lake. Soon a more sinister tone starts to creep in and the youth is carrying a large switchblade. Andrzej torments the young man, he even tosses ..
