On this episode of Supernatural…

Sam and Dean attempt to investigate mysterious abductions by demons.

Kevin and his mom seek help from a witch, Delta, in order to create more demon bombs. Delta betrays them to Crowley.

Crowley had been capturing future prophets and if Kevin wouldn't read the tablet, he'd get one of them to do it.

Castiel returns from Purgatory and reveals that he chose to stay.

Castiel saves Kevin, and the brothers send them to lay low with Garth.

Castiel is summoned by an angel named Naomi who demands that he report on the Winchesters, but that he will never remember doing so. It was she and her team of angels that saved him from Purgatory.