I've Got You Under My Skin
Cordelia's vision of a young family, Angel pays a visit and deduces that the family's son, Ryan, is possessed by a demon.
Wesley, discovering that they are dealing with an Ethros Demon, decides he will perform an exorcism. It's is a success, but the demon escapes. Tracking it to a cave, Angel and Wesley learn that Ryan was evil before he was possessed.
Ryan tries to burn his own house down is taken into custody as a result.