Once a Cop

When Tony arrives early and alone to a crime scene, he's confronted by a pair of fake FBI agents and a ghostly woman who instantly targets him. The 'agents,' Sam and Dean Winchester, get him out of there, and it seems like the trouble is over. When the ghost follows Tony to DC, Gibbs must join forces with the brothers to protect Tony and vanquish the threat. NCIS S5, SPN S2