Castiel wakes up from his comatose when Sam and Dean have to fight two Archangels for a new prophet, whom the brothers believe could defeat the Leviathans.
Castiel (Misha Collins) is back in the next episode of "Supernatural" after being left in the psychiatric ward in "The Born-Again Identity". Meg calls Dean and Sam that the former angel wakes up from his comatose and is talking, but soon he has to face an angry lady who gives him a slap in the face.
Meanwhile, Sam and Dean are looking after a teenager named Kevin, who turns into a reluctant prophet after getting hit by a bolt of lightening. The Winchester brothers believe Kevin holds the key to defeating the Leviathans but must fight off two Archangels who want him for their own purposes.
A preview for the episode additionally sees Dean getting frustrated when he has a sit down with Castiel.
"Reading Is Fundamental" will air Friday, May 4 at 9/8c on The CW. Rachel Miner reprises her role as Meg, while Osric Chau guest stars as Kevin.