“I Do Over” is episode four of season three of Eureka.
It’s the day of Stark and Allison’s wedding, and Carter is less than totally thrilled about it, especially as he’s the one giving Allison away. Just as the wedding completes, there’s a flash in the sky, and Carter restarts the day again. Simply thinking deja vu, he goes through the day again, until the same thing happens again at the wedding. When he tries to talk to people about what happened, no-one else can remember it, and Stark tells him it’s impossible.
As the repetitions mount up, Carter finds that things that happened to him start crossing over into the time loop. This isn’t good, as the things that are crossing over are the various injuries he’s getting each time. As the loops progress, Carter is getting steadily more battered. Could it be connected to whatever mysterious thing Thorne is doing?
Carter’s sister also turns up for a visit.