Video Nasty (1970)

Teen best friends, Billy and Con are in the final year of school and are going on one last hurrah when things are complicated by the unwelcome addition of Con's older sister Zoe. Seemingly simple friendships become complicated and complex family dynamics are made to withstand unprecedented pressures. The three teenagers go on an epic quest to complete a cult VHS collection, only to get mixed up in a gruesome murder investigation, becoming chief suspects and public enemies.