The tension between Supernatural‘s demon-hunting brothers is about to reach its boiling point. After weeks of accusations and disagreements about Dean’s new vampire pal Benny, things finally come to a head between the Winchesters in this Wednesday’s winter finale (The CW, 9/8c).

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“We have a situation where Sam may have, behind Dean’s back, kept more tabs on Benny than Dean realized,” previews executive producer Jeremy Carver.

Sam’s doubts about his brother’s monstrous friend are heightened when Martin (pictured below), the hunter keeping an eye on the vamp, starts to believe that a recent kill was the work of Benny and his fangs. Thus far, Dean has staunchly defended the enigmatic new character in his life. But will he continue to do so when this new evidence is presented? Or will he start to suspect that maybe his purgatory buddy isn’t keeping his nose as clean as he’d promised?

“It’s a little bit of both,” replies Carver. “That drives the heart of conflict [in this episode].”

For the younger Winchester, Benny’s true nature is clear. “An expression we use in the episode [is] Occam’s Razor,” explains Carver. “When something appears to be, it normally is. So how is Dean going to deal with the fact that Sam thinks Benny is someone that has to be dealt with right here and now? That drives Dean’s conflict about how to act with Benny and how to act with Sam.”

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Whichever allegiance he chooses, it can’t be ignored that Dean has repeatedly stuck by his creature pal, oftentimes instead of by his own brother. “Everything that Dean has said, everything that Sam has said regarding Benny, has not gone into the wind,” says Carver. “They’re very acutely aware of where they stand” – and it ain’t pretty.

For Sam, it’s “rather tough to see” the “surprising amount of faith, trust and love that Dean puts into Benny,” continues the EP, “especially with some things that Dean has said about Benny in comparison to Sam. It just speaks to how far apart these guys were driven” in the year during Dean’s disappearance.

Carver is coy about whether Dean and Benny’s time in purgatory will play a role in future episodes — there’s no glimpse of the war zone in the winter finale — but he does hint that a big payoff is coming with regards to those flashbacks of Sam’s relatively normal life. “Are they more than they seem? This week will answer some of those questions,” he teases. Viewers will also find out the identity of the mysterious figure who was watching Sam leave Amelia’s house in the season premiere. “Everything’s happening this week!” reveals the EP.

As for whether Sam’s remembrances of the past year, which are quite different in tone for the show and have received mixed reactions from fans, have been successful, Carver believes that “these next couple of weeks will fill out even more what we wanted to get across. I’m very proud and very happy with the flashbacks, and I think it’s a really interesting departure for the show to take.”