11:00 P.M.-12:00 Midnight - S1-E24
Corrected entry: In this episode we find out Nina is the mole but in one of the first episodes, the kidnappers ordered Jack to shoot Nina, which he did, though unbeknownst to them, he had previously put a bullet-proof vest on her. If she was their insider, why would they order her shot?
Correction: There were two moles inside CTU - Jamey Farrell and Nina Myers. It was Jamey who worked for Gaines (in the first half the season), whereas Nina worked for the Drazens directly. Gaines (who ordered Nina to be shot) had no idea that she was also an insider. It's doubtful that Drazen would reveal their 'contacts' identities to anyone - even Gaines.
Chimera ★