While still torn between his good and evil sides, Cole (Julian McMahon) comes to the rescue of Melissa (Amy Laughlin), a woman whose husband had been lured to his death by a bewitched Siren (Melinda Clarke). In their efforts to further protect Melissa, the Charmed Ones discover that the woman is destined to be a Whitelighter, just like Piper's husband, Leo (Brian Krause). The situation is complicated when both Cole and Phoebe fall under the Siren's deadly spell -- and complicated farther when Piper's still-unborn baby, sensing that his parents both need to walk in each other's moccasins a few miles, switches the supernatural powers possessed by Leo and Piper (Holly Marie Combs). ~ Rovi