"The Wounded" was the 12th episode of the 4th season and was written by Jeri Taylor.
The Enterprise is fired upon by a Cardassian vessel. They put up shields and get through to the other ship and it's captain says that another starship captain attacked one of their science outposts and goes on the assumption that the federation is now once again at war with the Cardassians.
Captain Picard informs starfleet command about the incident and the admiral confirms that a federation ship, manned by Captain Maxwell, did attack the outpost. Picards assignment is to intercept the Phoenix to prevent another attack on the Cardassians.
In a show of good faith, Picard invites the Cardassian captain on board the ship to help assist.
Meanwhile, it is learned that Chief O'Brien served under Maxwell's command and sits in on a staff briefing. O'Brien says Maxwell's family were killed in an attack by the Cardassians, leading Picard to suspect this may be a motive for his behavior.
Then the Enterprise enters the area of space where the Phoenix is, but isn't in time to stop it from firing upon and destroying a Cardassian supply ship with 600 persons on board.
Picard hails Captain Maxwell and convinces him to board the Enterprise to talk about what he's doing. Maxwell insists there are weapons on board the supply vessels and the outpost was a strategically located military base, not a science station as the Cardassians claim. Picard instructs Maxwell to head his ship back, with the Enterprise following, to the starbase where he will await further instruction, and justice, from Starfleet command.
Maxwell has his ship set a different course; it's on an intercept course to a Cardassian supply vessel. The Enterprise is set to launch torpedoes about Chief O'Brien asks the captain to board the Phoenix and talk to Maxwell. Their meeting is successful and Maxwell stands down when he realizes he cannot win the war and begins to come to terms with his tragic past.
Back on The Enterprise, Picard informs the Cardassian captain that his mission was to preserve the peace they've made with the Cardassians but also knows that Maxwell was right and that the federation will be watching.
This episode was well-acted and presented the nuances of conflict. There's no black and white, but a gray area that opposing sides must face in order to maintain the peace. We can resolve conflict without violence while staying watchful of the enemy. We can work together even while learning to build trust.