Are You There, God? It's Me, Dean Winchester

S4 E2: Sam and Dean are stunned when the spirits of Meg (recurring guest star Nikki Aycox - "Cold Case," "Ed") and Agent Henricksen (recurring guest star C. Malik Whitfield - "The Guardian") appear and accuse the Winchesters of failing them. Although rattled, the brothers must pull together to save Bobby (recurring guest star Jim Beaver), who is too crippled with guilt to fight off the angry ghosts of the young children he couldn't save.