After the passengers and crew of a private plane traveling from New Orleans to Washington D. C. are lethally poisoned, all evidence points to the missing chef, Abby's brother, Luca. Gibbs and the D. C. team work in conjunction with Pride and the New Orleans team to locate Luca and determine why a private tech company was targeted. (Sister City (2) aired on NCIS: New Orleans, season 2, episode 12.)