Nathan Fillion, Jon Huertas, Seamus Dever, Stana Katic Photo

From: Photo Flash: CASTLE's 'The Human Factor,' Airing 5/6

On CASTLE's upcoming episode, titled 'The Human Factor,' when Homeland Security inexplicably seals the crime scene of a car bombing, Castle and Beckett find themselves with two mysteries on their hands: who murdered the victim, a government whistleblower, and why are federal agents trying to take over the case? The plot thickens when they discover that the victim wasn't killed by a car bomb but by a missile from a military drone, on MONDAY, MAY 6 (10:01-11:00 p.m., ET) on ABC. Carlos Bernard guest stars as Jared Stack, a mysterious operative who may hold the key to solving the case.