Release Message:  When a temporarily maddened Dr. McCoy alters history and eliminates his time, Kirk and Spock follow him to prevent it, but the price to do so is high. Featuring Eddie Paskey as Lt Leslie.

Description:  When a temporarily maddened Dr. McCoy alters history and eliminates his time, Kirk and Spock follow him to prevent it, but the price to do so is high. Wikipedia: The crew of the Enterprise discover a portal through space and time, which leads to McCoy accidentally altering history.