Sam and Dean encounter a vampire hunter whose obsession may get them all killed.

One Year Later Dean’s escaped from Purgatory, though Castiel is nowhere to be found. However, Dean isn’t alone. He’s returned with a mysterious comrade-in-arms whose reason for escape is perhaps more than Dean bargained for. Meanwhile, Sam finds himself reconciling the life he discovered while Dean was gone with Dean’s sudden reappearance. As the boys struggle with their unexpected reunion, they make a shocking discovery that could lead them on a deeply personal mission to settle old scores. If only they could agree – is this a “family business” or isn’t it?

Kevin talks Sam and Dean into checking in on his mother. When they arrive, they see that Crowley has surrounded her with demons so they rescue her and take her along on their quest to find the tablet. However, they soon discover Kevin wasn’t kidding when he said his mother was a strong-willed woman after she tries to take on Crowley.

After Benny gets brutally beat up by some vampires, he calls Dean for help. Dean abruptly packs up and tells a confused Sam that he’s taking a "personal day." Benny confesses that he’s going after his Maker so Dean offers to help, flashing back on the many times Benny helped him and Castiel in Purgatory. Meanwhile, Sam uses his solo time to reflect on the life he left behind with Amelia. However, when things go bad for Dean and Benny, Dean calls Sam for help, which makes everything very complicated.

Sam and Dean are stunned when Castiel suddenly appears back on Earth with no memory of how he escaped from Purgatory. Meanwhile, Mrs. Tran enlists a witch to concoct a demon bomb, but the witch double crosses Mrs. Tran and turns her and Kevin over to Crowley.

Sam asks a hunter named Martin to keep an eye on Benny without telling Dean. However, when Martin tells Sam there was a vampire kill and he thinks Benny is responsible, Dean defends his friend. When Martin decides to take things into his own hands, things get messy and Dean is forced to make a very hard decision.

Naomi tells Castiel that Crowley is holding an angel captive and Castiel must rescue him before Crowley finds out their secrets. Castiel turns to Dean for help. Meanwhile, Sam meets with Amelia who asks him to make a choice: stay with her or leave and never contact her again.

Sam and Dean respond to a call from Kevin, who is terrified after hearing Crowley's voice in his head. After hearing Kevin's news, Sam and Dean team up with a reaper named Ajay, who helps them deal with the second trial from the Tablet. Meanwhile, Dean receives a visit from Naomi and realizes he must find Benny and ask for a huge favor.

Sam learns that former Men of Letters, Magnus, once built a magical box and Sam sets out to find it in the hopes it can cure Dean of the Mark of Cain. However, what he’s not prepared for is the deadly alarm system Magnus set up on the box. When Sam opens the box, he puts both his and Dean’s life in danger.

Sam and Dean investigate the mysterious death of a girl and the disappearance of another.