Sam and Dean have been building towards a confrontation since the first episodes of Supernatural season four. With Sam's constant lies about what he's been up to with Ruby, it was only a matter of time before Dean found and got mad. Dean's version of mad started last week with him locking Sam into Bobby's panic room. In tonight's episode, Sam is still locked in the panic room and tries to get Dean to let him out.

While suffering through demon blood withdrawal, Sam had a few less than pleasant hallucinations. First up was the demon Alastair who he imagined to be torturing him. While Sam screamed from the panic room, Bobby made himself and Dean a drink. Hunter Rufus called with something important.

Sam next imagined he was talking to a child version of himself. He tried to apologize to the younger Sam but the kid wasn't having it. He blamed the older Sam for ruining their chance for a normal life with all of his demon hunting ways. Kid Sam's eyes turned yellow when he admitted that maybe Sam couldn't run from what was inside of him.

Bobby tells Dean that more seals are being broken. He tries to get Dean to let Sam keep killing demons but Dean's not willing to hear it. Inside the panic room, Sam hallucinates that his mother is there. She tells him to use his evil demon powers for justice. She also says not to let anyone, even Dean get in the way. The fact that Sam believes any of this shows how bad off he is.

Dean calls Castiel and is mad when it takes him awhile to show up. Castiel tells Dean that Sam's likely becoming a monster. He reminds Dean that Team Heaven still believes Dean's supposed to save the world and not Sam. Castiel gets Dean to commit himself to serving God and his angels. When Dean tells Bobby, he's not exactly overjoyed about Dean signing up to be "the Angels' bitch." Then Dean reminds him that its trust the angels or let Sam trust a demon and Bobby loses his argument.

Sam has a more violent symptom of withdrawal that sends him slamming into walls and flying across the room. Bobby and Dean have to tie him up and Bobby gets more persistent about how this cold turkey attempt is working. Dean says if he dies at least he dies human.

Sam's last hallucination is Dean who alls Sam a monster, and at the same time the real Dean tells Bobby that his own limit. He won't let Sam become a monster.

Sam comes to again and the door opens. As he walks out Castiel looks on from underneath the stairs. Castiel closes the room back up and locks it. Dean and Bobby sleep as Sam sneaks out.

Anna appears and yells at Castiel for letting Sam out in the first place. Castiel reminds her that he has orders. He tells her she shouldn't have come and she gets the angel version of arrested when two angels show up and take her back to heaven.

Bobby pulls a shotgun on Sam just as he's about to leave. Sam tells him he won't shoot him and knocks Bobby out when he hesitates. Later Bobby and Dean check the panic room and assume a demon must have broke Sam out.

Sam gets an expensive looking room to throw Dean off his trail. Ruby shows up and explains she's been looking for Lilith. She tries to talk about things between him and Dean but Sam's only after the blood. In bed after, Ruby tells Sam his appetite has grown which means he's getting stronger. There's only two or three seals left and according to Ruby the last one can only be broken by the first demon Lucifer made. Of course the first Demon is Lilith.

Ruby suggests they go after the demon that's responsible for feeding Lilith. The said demon possesses nurses at hospitals and steals babies to bring to Lilith. She wants Sam to use the demon to find Lilith.

Dean finds their hotel room and tries to kill Ruby. Sam stops him and tries to get Dean to hear his side, but Dean's only willing to work with Sam if he gets rid of Ruby. Sam tells Dean he's not strong enough to stop Lilith so Dean tells Sam he's a monster. Sam punches him and Dean punches him back. Their fight is quick with the stronger Sam knocking Dean down. Dean tells Sam if he leaves they're done and Sam leaves anyway.

Next week it's the last chance for them to stop the apocalypse, and with Sam and Dean no longer working together anything could happen.

Supernatual Cast: Jared Padalecki, Jensen Ackles, Jeffrey Dean Morgan, Nicki Lynn Aycox, Jim Beaver, Katie Cassidy, more

Story by Lauren Attaway

Starpulse contributing writer