A former hunter named Martin, who is currently institutionalized, calls Sam and Dean for help investigating a case in the mental hospital. The brothers get themselves admitted as patients to check out the mysterious monster that is attacking the patients, but their incarceration pushes both to the breaking point as they unleash their inner demons against each other.
Elenco: Jensen Ackles , Jared Padalecki , Misha Collins , Alexander Calvert , Mark Pellegrino , Mark Sheppard , Alona Tal , Candice Accola , Felicia Day , Genevieve Padalecki , Jeffrey Dean Morgan , Julie McNiven , Katie Cassidy , Lauren Cohan , Osric Chau , Richard Speight Jr. , Rob Benedict , Samantha Ferris , Ty Olsson .