The premise--Tru Davies (Dushku) gets a job at a morgue, where the corpses occasionally wake up and ask her to save them. When this happens, her day restarts. Aided by her boss, Davis (Zach Galifianakis) and her brother Harrison (Shawn Reaves), she spends the repeated day trying to find out what happened to the victim, and how to keep them from landing once again on the slab in the morgue. As it turns out, her mother also had this ability, and late in Season One we are introduced to Jack Harper (Jason Priestley), as her opposite. Jack repeats days, too, but he considers it his duty to be sure people who were fated to die actually do, rather than saving their lives. This plotline carries into Season Two, building an ongoing backstory where Jack works to sabotage Tru's work. Without her knowledge, Tru's father assists Jack, opposing Tru. Unfortunately, the retooling of the show and the addition of Priestley weren't enough to bring in additional viewers.
Tru Calling isn't a great show, but it's not bad, either. It shares elements with Quantum Leap, an old favorite, especially in the first season, when each episode presents a standalone story. The addition of Jack didn't really help the show, in my opinion. This is partly because I just don't care for the way Priestley plays the character, but it also seemed to shift the focus of each individual episode. Before Jack came along, Tru had to sort through many often random circumstances to work out how and why she needed to save the current victim. After Jack, though, the focus became Tru vs. Jack, lending an element of predictability to each show that to me made it less interesting. Although even with only five Season Two episodes, the writers had already begun to add depth to his character, and bring up some interesting moral questions that mitigated this somewhat. (What if Jack was right? What if Tru really was meddling with Fate?) In at least one episode ("Enough"), Tru's motivations and actions really do seem to be wrong, and in another ("Last Good Day"), Jack himself questions his purpose. By the last episode ("'Twas the Night Before Christmas...Again"), Tru and Jack are working together, albeit reluctantly. One has to wonder how their relationship would have developed over the course of Season Two, and where the writers were taking the subplot involving Tru's parents. The Wikipedia entry for the series has information posted by one of the show's creators, with some thoughts about where the show might have gone. Overall, while it isn't exactly a television classic, it's too bad Tru Calling wasn't allowed a longer lifespan.