S1, E14: Prue tries to help a young boy, who's received his mother's witch powers after two thugs kidnap him to use his powers for their evil gain. Meanwhile, Leo returns and wants to declare his love for Piper, but can't because angels and witches cannot get together. After he lets Phoebe in on his secret, she tries to get Leo to tell Piper the real truth behind his leaving town for good this time.