The Enterprise encounters a derelict alien ship that holds an ancient, hostile entity.
While exploring the outer rim of the galaxy, the Enterprise is dragged by intense gravity into orbit around a dead star. It finds an alien pod ship about 300 million years old caught in the same pull, built by an insect-like race and since taken over by a malevolent energy being.
The entity moves into the Enterprise, seizes its systems and tries to force Kirk to carry it to other worlds. Kirk fakes a suicide run toward the dead star that is really a slingshot manoeuvre, and the entity flees. Written by Samuel A. Peeples, the episode premiered the animated series on 8 September 1973.