This book is the first in the series of novelizations of the episodes of the animated Star Trek series. The episodes featured are: Beyond the Farthest Star - the Enterprise investigates an unusual radio signal and finds itself next to a gigantic and ancient star ship of unknown design and origin. Upon exploration, they learn that a strange and dangerous creature invaded the ship and the crew self-destructed rather than allow the creature to take over the ship. That creature manages to enter the Enterprise and the crew must engage in very heroic actions in order to defeat the creature and return to Federation space: Yesteryear - Kirk and Spock accompany a team of historical researchers through the guardian of forever. Great care is taken to make sure that no changes are made in the timeline, but when they return, no one on the Enterprise recognizes Spock. After investigation, it is determined that Spock must travel back in time to his home planet of Vulcan and give critical aid to himself when he was a child: One of Our Planets is Missing - in this episode, a giant cloud-like creature journeys into Federation space and consumes planets for food. After destroying an uninhabited planet, it is moving towards Mantilles, a planet with 82 million inhabitants. The Enterprise is the only thing standing between the creature and the destruction of the planet.