The wait is finally over! First of all, congratulations for surviving two painful months without Supernatural. The long hiatus has certainly been difficult to endure with all the big mysteries and cliffhangers left by "Abandon All Hope" but I'm sure "Sam, Interrupted," the 11th episode of the fifth season, is worth the wait.
When we last saw Supernatural, Sam and Dean tried to kill Lucifer with the Colt only to discover that it can't kill him. Lucifer then sacrificed several demons to summon Death, while Castiel managed to free himself from his trap and took the brothers to Bobby's where they silently grieve over Ellen and Jo's death. You can catch up on the full recap in this article.
As you may have already heard, the first Supernatural episode of the year finds Sam and Dean in a mental hospital when a former hunter named Martin Creaser, who has ended up in the psych ward, calls for help. The brothers use their real-life supernatural experiences as their entry ticket to get themselves admitted as patients in attempt to investigate the mysterious happenings afoot the hospital.
It's bad enough that patients are being attacked by a strange force but Sam and Dean's confinement makes matters even worse as it pushes them to their breaking point while they unleash their inner demons against each other.