S4 E24 | 05/22/07
Angel of Death
Twisted Sister -- Forgoing NCIS procedure, McGee risks his career when he takes matters into his own hands after his sister appears at his door bloodied and confused. As McGee struggles to piece together his sister's whereabouts the night before, he discovers that the NCIS team is investigating the murder of a Navy sailor who had a previous relationship with his sister. Meanwhile, as separate clandestine romantic relationships bloom for both Abby and Tony, the NCIS team discovers McGee has a secret of his own.