Worf is put on trial after the Defiant destroys a Klingon civilian transport. One by one, Worf's friends are forced to testify, either bolstering Worf's defense or damaging it. For example, O'Brien confesses he would have not done what Worf did.
The Klingon Advocate even provokes Worf into attacking him, which bolsters his case since the Advocate was unarmed at the time.
In the end, evidence is discovered that hints the entire affair was set up to frame Worf. Sisko still has criticisms of what Worf had done but he tells the Klingon he will make a fine captain some day.