While the war between the Federation and the Dominion continues, Klingon General Martok docks his ship to take on reinforcements. Worf is shocked to see that one of the new recruits is his estranged son, Alexander. Worf reveals that he sent Alexander to live with his foster parents on Earth years before, after the boy showed no interest in becoming a warrior. Martok encourages Worf to mend fences with his son, but the attempt soon deteriorates.
In the mess hall, Alexander engages in a fight with Ch'Targh, a grizzled Klingon veteran. Worf, seeing that the boy is losing badly, stops them. Angry and humiliated, Alexander tells his father that he had no right in interfere. Ch'Targh echoes the young Klingon's feelings, reminding Worf that he won't be able to come to his sons aid when he is fighting the Jem'Hadar.
Later, the bridge crew responds to an appaarent Jem'Hadar attack. When the expected torpedoes never hit, Worf realizes Alexander simply forgot to erase a battle simulation program from the sensor display. The others laugh about the incident, actually welcoming Alexander into their ranks. Worf, however, is angry and embarrassed that his son is the ship's fool.
Determined to make a warrior out of Alexander, Worf spars with him using a variety of Klingon weapons. The boy's skills are lacking, and the practice session turns into an angry confrontation. Later, Martok informs Alexander that he is being transferred off the ship at Worf's request. Devastated, Alexander confronts his father and accuses him of trying to get rid of him, just like when he was a boy. Worf is stung by the truth of these words, but has no time to mull over them — the ship has come under Jem'Hadar attack.
When Alexander's sensor panel is destroyed during the battle, he and Ch'Targh volunteer for the deadly task of sealing a plasma leak. Realizing he may never see his son again, Worf is filled with emotion. Luckily, the Jem'Hadar ships are destroyed, and Alexander and Ch'Targh successfully complete their task. Worf apologies for the past and promises to teach Alexander to be a warrior if he will teach him to be a father. To make their reunion complete, he and Martok formally welcome Alexander into the House of Martok.