Nick is holding a female demon hostage. He's looking for something and wants to know what she knows. Then, he kills her.
Dean is packing a bag and then goes to talk to Sam. Something is obviously bothering him. He tells Sam he's going to see Mary and wants to go alone.
Sam talks to Mary on the phone. Bobby left because of his son and they needed space. Sam tells Mary about Dean and that he's worried about him because he hugged him.
Sam goes into the storage room and notices a book is missing -- the one Dean took with him. Sam is eating a burger with Donna. He wants to know what's going on with Jody and everything else. It's like he's doing a goodbye tour.
Dean arrives at Mary's cabin. She's out back shooting pumpkins. He wants to make Winchester Surprise -- a dish he loves. When she leaves for the grocery store, he takes his bag and goes to the shed. Michael is still trying to get out and it's affecting Dean.
Dean starts building something.
Mary is at the grocery store and the cart kid tries to help her with groceries. After she leaves, Nick shows up and asks him about her. He denies knowing anything and then he makes a call.
Nick is driving around and gets pulled over. It's Donna. He's in a stolen van and she asks about that as well as his inquiries about Mary.
While she's checking the mobile fingerprint scanner, he gets out of his cuffs and overpowers her.
Dean is acting very strange and she calls Sam to tell him. She doesn't want him out there yet until she figures it out. Dean is having conversations about the past with Mary at dinner.
When Dean's asleep, Mary goes to the shed to see what he was doing in there. She doesn't like what she's seeing. Inside, Dean gets a phone call. When Mary leaves the shed, Nick is out there.
Donna tells Dean Nick is going after Mary. Dean goes outside and Sam is there. Mary is gone.
Nick tells Mary how he found her. He's looking for a demon named Braxis, the demon who killed his family. She tells him Braxis is dead but he tells her he trapped Braxis in a box and he wants to know how. That must be what Dean is building.
She tells him she can take him to the box.
Dean, Sam and Donna search for Mary.
Mary takes Nick to a storage place. There's a booby trap and he sees it before becoming a victim. The box is in a locker that she doesn't have the key for. He breaks open every locker because she won't tell him which one. It only takes him three.
Dean and Sam are driving to find Mary and Dean is pissy as hell.
Nick got himself a vessel to release Braxis. Mary tries to fight off Nick, but she loses. She won't open the box for him so he tries figuring it out and he doesn't succeed.
He comes up with an alternative and decides to drill into it which works. Braxis enters the guy. Nick asks him about his family and Braxis knows who he is.
Braxis tells Nick he has to kill Mary if he's going to talk but Sam and Dean show up just in time.
Nick breaks the circle and Braxis escapes then he tells Nick he was ordered by Lucifer to kill his family.
Nick kills Braxis but Donna shoots him in the foot and Mary knocks him out.
Mary tells Dean she knows what he's doing and building in the shed. Dean tells Sam about and shows him the box he's building. He wants to be buried at sea.
Billie told Dean this was the only way for him to defeat Michael which is why he built it. Sam is pissed that Dean wasn't going to tell him about his farewell tour. Dean tells him he's not going to be talked out of it and he wants Sam's help.
Sam agrees to help him.