Piper, Phoebe, and Paige inadvertently expose themselves as witches in front of Jason, causing him to leave Phoebe. Richard casts a spell to free himself of his family's negative karma , but accidentally channels the spirit of Mata Hari , a double agent against Germany for France during WWI , into Phoebe. Phoebe decides to get revenge on Jason by arranging for a demonic firing squad to kill him. Meanwhile, Piper and Paige try to vanquish a group of Swarm Demons, the last on Chris' list of the most significant threats to Wyatt.