First to say that I never imaging this ending at all and when I saw it I just completely knew why won the Emmy for Directing 'Steve Shill'. Dexter 'Michael C. Hall' always kills his victims in just seconds after investigating them about some evidence to prove they are guilt of a murder. But with Arthur Mitchell or Trinity Killer 'John Lithgow' it wasn't in that way. He was worried about the idea of how his family would be after years living with him and with his dark passenger, so Trinity looks to Dexter like a 'mentor'. He screwed up everything when Trinity followed him to the Miami Metro Police Department and discover his real identity. 'Hello, Dexter Morgan' were the worst words which Dexter wanted to hear from Trinity's mouth. It forced him to look for an opportunity to king nap him and kill him but the things got worse and worse. Miami Metro Police were investigating Trinity as the same time Dexter wanted to kill him. For the entire season, Harry told messages about his family and if he would be able to live the family life, and the killing life at the same time. So after Debra, Masuka, Quinn, Batista and LaGuerta found Dexter in Trinity's Harry told Dexter to leave his family and go away. Dexter loved his family and he wanted to take care of them forever he was ready for that, so he didn't wanted to leave them and go away, especially if Trinity was out there. And the other big moment of the episode was when Debra seemed to told Dexter that she knows who really was. She knew that his biological mother Laura Moser was with his adoptive father Harry Morgan and knew that the Ice Truck Killer was his blood brother and nothing else that's it but Dexter was really scared about what was gonna tell him. After Dexter and Rita talked about the honeymoon and the kids went to Disney World Dexter just had two things to do, Find Trinity and kill him. Dexter finally found him in the act of leaving the city and disappearing. After a whole season to kill Arthur at last kill him. He was imaging when he was in the ocean dropping Trinity's parts of body how his life would become and was normal until he came home. In the last second Rita came home to get her identification but, someone left Dexter a big surprise. Rita was dead in the bath tub and Harrison in the ocean of blood of her, just like the death of Dexter's Mother. He realized for sure that he was the responsible for the Rita's Death and that he couldn't kill and have a family at the same time. That's why Harry said him that killers are always lonely. The Biggest Twist and shocking moment of the series that makes this episode the Best of the series in my opinion.