I am up to around episode 18 of season 5 now. And I love the episode Power Play where Deanna, O'Brien, and Data were taken over by beings that had escaped from a prison colony on a distant moon. They came aboard the ship and took over the bodies of Deanna, O'Brien and Data and pretended to be the souls of crew from a crashed Star Fleet vessel. They were attempting to get Picard to let them free prisoners from the moon, by tricking him into thinking they wanted to recover their bodies and lay them to rest.
I loved seeing Deanna be a villain, she was great as were Data and O'Brian. Data was very menacing, different from when he plays his evil twin Lore. I liked the tension of the episode too. With them holding the crew hostage. I always like it when Star Trek goes a bit dark. It was like Star Trek does Die Hard only with Ten Forward instead of a Sky Scraper. lol