When Henry comes to, he's in the Impala with Dean at the wheel. They apparently stopped somewhere along the way and got a new window for Baby. "Sorry about that," Dean says. "No, you're not," Henry says. Dean tries to explain how he wasn't able to save his father, so he'll always try to save Sam. "He's the only family I've got," Dean says... to his grandfather.
Dean and Henry arrive at the processing plant where Abaddon and Sam are waiting. Henry pleads with Dean not to go through with it, but Dean forges ahead. "That's the problem with you hunters," Henry says. "You're all short-sighted." Dean scoffs. "Yeah, at least we're not all extinct." Dean stuffs the box into Henry's pocket and gives him a little shove. Henry doesn't budge until Dean pulls a gun on him. Henry, his hands behind him, starts across the floor towards Abaddon. At the same time, Sam heads towards Dean. "Henry, I'm sorry," Sam says as they pass. He and Dean make for the door, but Abaddon whammies it closed. "We had a deal," Dean reminds her. She laughs. "Surprise! I lied." She shoves her hand into Henry's gut. "You're not the only one," he says. He shimmies out of his handcuffs, pushes a gun under Abaddon's jaw and pulls the trigger.
In a flashback, we see more of Dean and Henry's conversation in the Impala. They're hatching a plan to attack Abaddon somehow.
In the present, Abaddon is just recovering from her gunshot wound. She reaches into Henry's pocket for the box and pulls out a deck of cards. She realizes she's been tricked. "Where is it?" she shrieks. The overhead lights pop and spark with her fury. She tries to spit some demon smoke into Henry's mouth, but it only reaches a few inches before bouncing back to her. Henry drops to the floor and Sam rushes over to him. Abaddon shrieks some more. "Why am I stuck!?"
Another flashback to the car ride. Henry carves a devil's trap into a bullet. Dean is surprised. In the recaplet, I thought Dean had come up with the idea, because he's been such a super-hunter since Purgatory, but it seems clear that it was Henry's plan. "You're going to have to get close," Dean says. "And close could get ugly." Henry knows: "You do that for family."
Abaddon laughs. "You still didn't kill me," she says. "Yeah, but you'll wish we did," Dean says, and lops off her head with a machete. She falls to the ground in two, quiet pieces. Dean says he's going to slice her up and bury the pieces. But... wouldn't only the part of her that's in the head be stuck? Clearly I'm overthinking this. Meanwhile, Henry is slowly dying in Sam's arms. A hand to the gut doesn't seem too fatal. They could probably rush him to a hospital, or maybe Castiel could heal him like he did with Kevin's hand, but then we wouldn't get this tearful farewell scene. Dean thanks him for the job well done. Henry's sorry for judging them so harshly for being hunters. "I should have known better," he says. "You're also Winchesters. As long as we're alive, there's always hope." He clasps hands with Sam and Dean, says he knows he would have been proud of John. With one final breath, he slumps against Sam. Sam looks down and realizes Henry has pressed the box into his hand. LEGACY!