Federation - The Enterprise is confused with a rift in space-time that deposits a heavily damaged Federation starship before it. The ship, the USS Alexander, reports that it has returned from 8 days in the future, where the Federation has been destroyed, just before the ship explodes. The Crew of the Enterprise must discover the cause of the destruction and prevent it from happening.
Sentinel - A Federation Science ship, observing a primitive race on an alien world, is suddenly scanned from the planet. The Enterprise is called in to investigate.
Light and Darkness - The Enterprise is sent to answer a distress call on a barren planet, home to only two life forms, each of which claim they are morally obligated to destroy the other. Kirk must resolve the situation.