DS9 Season 4 Episode 18 Rules of Engagement

Plot

Worf commands the Defiant on an escort mission to guard Cardassian medical vessels. While under attack from Klingon raiders, a vessel de-cloaks in front of the Defiant. Expecting the vessel to be a Klingon warship, Worf orders it fired upon immediately without visual confirmation. However, the destroyed ship turns out to be a Klingon civilian transport, and the Klingon Empire wants Worf tried in their court.
Admiral T'Lara presides over Worf's extradition hearing aboard Deep Space Nine. Captain Sisko serves as Worf's defense counsel. Ch'Pok, the advocate representing the Klingon Empire, argues that Worf attacked due to uncontrollable bloodlust and was motivated by seeking revenge against the Empire for his family's dishonor, rather than following proper rules of engagement. He calls Worf's friends and acquaintances to testify. Jadzia Dax testifies that, in her experience, Worf is capable of restraining his bloodlust, but that he played a holosuite game before the mission in which he played a warrior who murders civilians. Quark testifies that Worf stated before the mission that he was hoping for an attack. The combat-experienced Chief O'Brien says that he would not have given the order to fire if he had been in command. After Worf testifies that he would never attack an unarmed opponent, Ch'Pok baits Worf into attacking him, contradicting his claim.
In the end, Constable Odo's investigation uncovers evidence that the names of all the 441 people who were reported to have died on the transport were the exact same names of the people who were reported to have crashed on a distant planet three months prior to the battle. Sisko concludes that the entire incident was staged by the Empire to frame Worf for the purpose of smearing the Federation. Despite having no civilian deaths on his conscience, Worf admits that he did accept the mission assignment because he was hoping for vengeance against the Klingon Empire. Sisko reprimands Worf for accepting the mission for that purpose, and for not following Starfleet regulations and identifying the vessel before firing upon it; but he tells him that he will make a fine captain some day.