Dr. Howard Machen (Kirk Alyn) and his students have been raiding California's Indian graveyards for archeological artifacts, a criminal practice that the university wants him to stop. After being ordered to make a complete inventory of his illegal finds, Machen regretfully withdraws from the latest field trip, but sends a group of students to dig without him. The young people stop at a remote gas station and receive a warning from an old Indian man (George Randall). He tells them to steer clear of Black Tree, where a great battle took place a century ago that returned many braves to the earth. The students find the location and an excavation yields plenty of ancient items, but strange things start happening and soon flaky D.J. (Jo Ann Robinson) is claiming that she senses evil about them. Her suspicions are confirmed when Randy (Richard Hench) is possessed by the spirit of Black Claw, a brutal Indian warrior who was known for dabbling in black magic. One by one the expedition is dispatched with arrows, clubs, and tomahawks and their skulls are peeled clean. Horror cult figures Forrest J. Ackerman and Carroll Borland make cameo appearances as faculty members in Scalps, which was an early film from prolific exploitation director Fred Olen Ray.