A distress call from Lt. Noonien-Singh compels Spock to disobey orders and take the U.S.S. Enterprise and its crew into disputed space, risking renewed hostilities with the Klingons in a bid to aid their shipmate.

Uhura seems to be the only one who can hear a strange sound. When the noise triggers terrifying hallucinations, she enlists an unlikely assistant to help her track down the source.

An accident while investigating a time portal sends Ensign Brad Boimler through time from the twenty-fourth century, and Captain Pike and his crew must get him back where he belongs before he can somehow alter the timeline.

An accident with an experimental quantum probability field causes everyone on the U.S.S. Enterprise to break uncontrollably into song, but the real danger is that the field is expanding and beginning to impact other ships—allies and enemies alike.

When the U.S.S. Enterprise investigates an attack on a colony at the edge of Federation space, Captain Pike and his crew face the return of a formidable enemy.