Sam and Dean investigate a case where people are suffering violent deaths after hearing a mysterious song.

Sam and Dean get a lead on Kelly Kline’s whereabouts. Mick drops by the bunker unexpectedly and decides to join the hunt.

Sam and Dean are alarmed when they learn hunters are being killed by suspicious “accidents” all over the country. They decide it is best to find Mary and make sure she’s safe. Meanwhile, Toni is back in the states and she and Mary face off.

Sam and Dean are visited by an old friend. Castiel investigates the disappearance of a local teen.

Dean goes off on his own to take on a case. Meanwhile, Castiel has an idea of how he can help Sam track down God.

Sam, Dean and Castiel’s continued search for a way to defeat Chuck leads them to unexpected places and toward unlikely allies.

Sam and Eileen are faced with the brutal truth. Meanwhile Dean and Cass work together in the hopes of getting a step ahead of Chuck.