Angel Heart

S10 E20: When Claire Novak gets a lead on her mother, Amelia (guest star Leisha Hailey), who's been missing for years, Castiel asks Sam and Dean to help her. Feeling guilty for what he did to the Novak family, Castiel wants to make amends by reuniting Claire with her mom. However, when they find out what took Amelia, they realize there is a chance Claire may not get her happy ending.