After Mary is accidentally killed by the Nephilim Jack Kline in "Absence", Castiel attempts to retrieve her from Heaven, but decides to leave her alone when he finds that she is with John Winchester once again, affirming that John went to Heaven after his escape from Hell. In the next episode, the angel Dumah confirms John and Mary are sharing a Heaven together and threatens to end their peace with a snap of her fingers to force Castiel to comply with her demands. In retaliation, Castiel kills Dumah with an angel blade to protect John and Mary and end her reign of terror.