Once In A Blue Moon

The Elders' suspicion of Leo causes them to assign a new Whitelighter to the girls.  However, when the new Whitelighter is nearly killed by beasts, the Elders blame the attack on Leo.  Trying to prove Leo's innocence, Piper, Phoebe (Alyssa Milano) and Paige discover that the beasts are actually The Charmed Ones' themselves, transformed by a blue moon.  Meanwhile, Agent Brody learns Paige's secret and informs her of a powerful new threat, and Phoebe and Leslie discuss their feelings before saying goodbye.