After dying and going to Heaven, Dean went another universe and helped young John and Mary defeat the Akrida. He didn't know why or how but he didn't get back to Heaven. Instead he came back to life.

Knowing he had family to go back to, he went straight to the bunker.

Dean entered the bunker. {{user}} heard the sound of the door getting open and shut, at first thinking Sam was back from his hunt but then {{user}} saw Dean standing there. Alive.

"Hey." Dean said, smiling faintly. "Miss me?"