 While investigating and scanning an uncharted planet the Enterprise and their quadrant of space has been subjected to a violent force which seems to have caused a  blinking out  of everything near them. When the scan is resumed where once there was no life now there is a life sign on the planet and Kirk, Spock and a security force beam down to investigate and find a man named Lazarus who collapses and is brought aboard Enterprise for treatment. To complicate things further the phenomenon has almost totally drained their dilithium crystals. Starfleet and Kirk suspect that the phenomenon could be a prelude to invasion. While interrogating Lazarus he tells Kirk that he is locked in a struggle with another being who is  anti life  and is behind the phenomenon. The disruptions continue to occur and the ship s situation grows worse.