After a Cardassian warship fires on the U.S.S. Enterprise, the ship's captain informs Picard that he is acting in retaliation against a Federation starship that has recently destroyed an unarmed Cardassian space station. This is unusual because there is now a treaty between the Federation and the Cardassians, who were once bitter enemies. As a goodwill gesture, Picard invites the Cardassian captain aboard to aid in the search for the renegade Federation vessel, despite the objections of some crew members who still mistrust their former enemy. Starfleet informs Picard that the errant Federation ship is the U.S.S. Phoenix, commanded by Captain Benjamin Maxwell.
Picard asks Transporter Chief O'Brien, who once served under Maxwell, for some insight into the man. O'Brien reveals that the captain's family was killed by the Cardassian militia before their truce with the Federation, but cannot believe he is seeking vengeance. At that moment, the U.S.S. Enterprise locates the Phoenix. Macet, the Cardassian captain, tries to convince Picard to reveal the ship's location, but Picard refuses. Later, Picard determines that the Phoenix is pursuing another Cardassian supply ship. When the U.S.S. Phoenix fails to acknowledge the Enterprise's calls, Picard orders Worf to make the ship's coordinates available to the Cardassians.
A nearby Cardassian warship sets out after the U.S.S. Phoenix, but the Federation starship destroys it and the cargo ship as well. Soon afterwards, Data locates the U.S.S. Phoenix, and the U.S.S. Enterprise intercepts it. Captain Maxwell transports aboard, and after a warm reunion with O'Brien, goes on to explain his actions to Picard. He informs his fellow captain that he believes the Cardassians are rearming and have developed one of the most powerful weapons in the galaxy. However, he lacks proof of his accusations, and Picard informs him that he must be returned to a starbase to face a board of inquiry.
Maxwell agrees to follow the U.S.S. Enterprise to the nearest starbase, but the Phoenix almost immediately changes course and begins pursuing another Cardassian vessel. Maxwell insists to an angry Picard that the Cardassian ship is transporting arms. Macet denies the charge, but refuses to let a Federation member board the ship. Maxwell continues his pursuit, daring Picard to board the Cardassian ship to see for himself. Instead, Picard threatens to turn his weapons on the U.S.S. Phoenix if it does not retreat. During the ensuing standoff, O'Brien transports to the Phoenix, where he is able to convince Maxwell to stop the killing and return to the U.S.S. Enterprise. As the Enterprise heads towards a starbase, Picard warns Macet that, while he went after the Phoenix to avoid starting a war, he knows Maxwell is right about the rearming, and tells him that if they don't cease, he will lead the charge against the Cardassians in battle.