Castle and Martha are trapped as armed bank robbers dressed in hospital scrubs and using names of TV doctors take hostages. Beckett was on the phone with Castle when the action started. The lead robber, who goes by Trapper John, will only talk to her. Looks like Beckett has gone from top homicide cop to instant hostage negotiator. Trapper John promises that if she messes with him, he’ll kill Castle first.
Castle realizes this isn’t an ordinary bank robbery. The hostage situation was planned so that the bad guys could have time to look through safe deposit boxes. If Castle can figure out who owns the box Trapper John is interested in, he may be able to figure out his plan. Speaking of plans, Trapper J wants a bus to take his crew and the hostages to the airport. He’ll release a pregnant woman there, but everyone else will go along for the ride.
Using a reflection caused by Martha’s bracelet, Castle is able to relay a Morse code message to Beckett outside regarding the safe deposit box. It belongs to a married couple named Agnes and Gideon Fields. They both access the box monthly. On the inside, a panicky hostage says he spotted some explosives in a robber’s bag. Castle calms the guy down by promising that he’ll figure out a way to save the day.
Ryan and Esposito discover that Agnes Gideon has been dead for at least a week. Her apartment had been professionally bugged. Back at the bank, panicky hostage guy has an epileptic seizure. Trapper John will let a paramedic help, but he pushes the delivery time on the bus from three hours to 20 minutes. Beckett dons an EMT uniform to tend to the sick man. She tells him that there are people out there who care about him and that’s she’ll get him out of there. Castle knows those words are really meant for him.