While on shore leave on the planet Argelius II with Dr. McCoy and Captain Kirk, Chief Engineer Scott finds himself accused of murdering an exotic dancer he met in a nightclub. He has no recollection of the incident but is found standing over the girl with a bloody knife in his hand. For Mr. Hengist, the chief administrator, the case is cut and dried, but Jaris, the planet’s leader, suggests that his wife chair a séance to identify the killer. Tragedy strikes again, still pointing to Mr. Scott as the culprit. Kirk suggests they retire to the Enterprise where they can use its computers to determine if Scott is lying and who the real culprit may be.