Plot hole: The first time the day happens, Paige is quickly identified as the victim of a drug overdose. However, we find out later that she actually died by violent strangulation. Yet the only sign of trauma on the corpse was minor hemorrhaging in her eye. There should have been obvious signs of the confrontation, starting with huge bruises on her neck.
Plot hole: The first time the day happens, Tru tells Luc that Mark called her, and later she tells him that he wants to talk to her, and Luc is fine with that because he trusts her. The second time, knowing that Mark was killed, she decides that she should agree to meet him when he first calls. But she lies to Luc about what she's doing. Why? She knows that he wouldn't have a problem with what she's doing, but instead she tells a lie that conveniently drives the episode's romantic plot.
Plot hole: There doesn't seem to be enough information about Mark's stabbing for Davis' computer program to determine how tall the attacker was. The main thing that's missing is any information about the angle of the knife's penetration. Without that, there should be no way to obtain the killer's height.
Plot hole: When Tru realizes that the yellow-handled knife Lindsay bought was the murder weapon, she gets rid of it. As a result, Lindsay needs to borrow a knife from Tru's neighbor so she can slice vegetables. The fact that Lindsay bought a knife for Tru, combined with the fact that Lindsay couldn't find one later, implies that Tru doesn't have a suitable knife of her own. But Tru served cut fruit to Harrison and his date several episodes ago, so she must already have a knife like that. In fact, pretty much everybody does. And there's no indication that Tru went around hiding all of her knives. In fact, the episode focused on that one, yellow-handled knife to an overly dramatic extent that bordered on inadvertant comedy.
Plot hole: In the episode "Closure," Harrison told Tru that he had lost interest in Lindsay, and was going to break things off with her. In this episode, they're still all coupley. Moreso, in fact, than earlier. We were never shown any developments in Harrison and Lindsay's relationship between the two episodes.
Plot hole: Why hasn't Tru met Luc? He came to the morgue very late the first time the night happened in the previous episode, after Marco scared Tru. Even though Tru seemed to stay at the bachelor party very late the second time the day played through, she had gotten into work by the time Marco tried to scare her again, so she should have still been there when Luc came in.
Plot hole: How did Candace get voted Reunion Queen the first time around? She acts like a total bitch to everybody we see her in scenes with, all we ever hear about is how many people hate her and probably wouldn't mind seeing her dead, and her comments when she accepts the award ("I can sort of remember some of you.") make it clear that she hasn't kept up with anyone.