A bumpy flight is never just a bumpy flight where Richard Castle is concerned and on Castle Season 7 Episode 21 the turbulence turned out to be murder, literally. When an Air Marshal is killed during a flight to London, Castle is called up to help figure out who the killer is and whether or not they intend to bring down the plane.

Watch Castle Season 7 Episode 21 Online

Alexis proves to be a help as she uses her cell phone to show Lanie the murder victim's wounds and the two of them manage to deduce that the man was killed via blunt force trauma to the head before being left in the baggage compartment of the plane. 

When Beckett and team find out that the flight includes a passenger with a fake passport and ties to the terrorist group ISIS, things get serious and Castle worries that he's never done a solo interrogation before.

Beckett assures him that he's been with her for countless interrogations and she has complete faith that her husband can pull this off and get everyone back on the ground...but do they have the right man?

There's no need to miss a minute when you can watch Castle online now, here at TV Fanatic. 

C. Orlando was a TV Fanatic Staff Writer. Follow her on Twitter.