En route to Ferenginar, Jake and Nog are attacked by a Jem'Hadar vessel. When they are suddenly beamed aboard the U.S.S. Valiant, a Defiant-class warship, Nog recognizes the crew of young adults as Red Squad, an elite corps of Starfleet cadets. The 22-year-old captain, Tim Watters, explains that his crew, originally on a training mission, became trapped in Dominion space when the war broke out. All of the regular officers were killed, but before he died, the captain ordered Watters to assume command. With Starfleet unaware of the situation, Watters is trying to complete the Valiant's mission to gather data on a new Dominion battleship. Caught up in Watters's fervor, Nog agrees to join the crew as Chief Engineer.
While Nog and Watters hit it off, the captain is less enamored of Jake, the only civilian on the ship. When a member of his crew, Chief Collins, becomes homesick after speaking with Jake, Watters calls the young Sisko into his office and warns him to stay away from her.
Nog successfully completes his first assignment, which is to adjust the Valiant's warp capabilities, by making the same modifications he once saw O'Brien make to the Defiant. He proudly tells Jake of his accomplishment, but his friend is upset that Nog joined the Squad so quickly. Their conversation is suddenly interrupted when the ship goes to Red Alert — the target is in sight.
The crew carries out their mission without being detected, but Watters rallies them to now attempt to destroy the enemy ship. Although Jake says that the plan is too risky, Watters only has to remind the group that they're Red Squad — capable of doing anything — and the room erupts in cheers. Even Nog gives the plan his support. Later, Jake confronts his friend over what he believes is a suicide mission and reveals that he has spoken with Collins against orders. Watters, secretly watching on a monitor, has Jake arrested and sent to the Brig.
The battle begins, and the Valiant sustains heavy damage. When the torpedo specially rigged to destroy the Dominion ship doesn't work, the enemy retaliates by unleashing an all-out attack. Soon, Nog and Collins are the only two left standing. After freeing Jake from the Brig, the three manage to flee in an escape pod moments before the Valiant explodes. The Defiant picks up the three survivors, and Nog, shaken by the experience, resigns from Red Squad.