NCIS: Season 2, Episode 22

2 - 22: SWAK

All hell breaks loose at the NCIS office when Tony opens a mysterious letter containing a small puff of white powder which may be a deadly bacteria. Kate calls for help and as a precaution, she and Tony are put into a bio-hazard isolation room while McGee and Gibbs are left to discover who sent the envelope and their reasons for doing so while searching for a cure to help their friends before it's too late.