Descriptions to go along with the titles:
Ep 21: There's Something About Mary : MARY VS. TONI BEVELL – Sam (Jared Padalecki) and Dean (Jensen Ackles) are alarmed when they learn hunters are being killed by suspicious “accidents” all over the country. They decide it is best to find Mary (guest star Samantha Smith) and make sure she’s safe. Meanwhile, Toni (guest star Elizabeth Blackmore) is back in the states and she and Mary face off. Writer: Brad Buckner and Eugenie Ross-Leming Director: P.J. Pesce
EP 22: Who We Are: FAMILY - Caught in a dangerous situation, Sam (Jared Padalecki) and Dean (Jensen Ackles) only have each other to rely on. Meanwhile, the fight between the American Hunters and the British Hunters comes to a head. Writer: Robert Berens Director: John Showalter
EP 23: All Along the Watchtower: EPIC SEASON FINALE - Lucifer (Mark Pellegrino) battles Sam (Jared Padalecki), Dean (Jensen Ackles) and Castiel (Misha Collins) for control of his unborn child. Writer: Andrew Dabb Director: Robert Singer