Beckett is still plenty peeved at Castle for looking into her mother’s murder against her wishes, yet Captain Montgomery forces her to chat with a reporter who is jazzed to write about her crime-solving partnership with Castle. But when a murder victim is found hanging in a tree, Beckett reluctantly teams with Castle once again. Their investigation takes a strange turn when armed men kidnap the body en route to the coroner, leaving Castle and Beckett to delve into the world of drug smuggling, the Russian mob and high stakes poker in Chinatown.

A man is found dead on the branches of a tree. The man, John Allen, was suffocated. Medical examiner Parish‘s preliminary exam indicates that the victim was dead before being tossed off the roof. Beckett suggests that Castle (and the reporter) go with Lanie to the morgue while she, Ryan. and Esposito do “boring cop stuff”.

Suddenly, the ambulance screeches to a halt and the doors fly open. Men wearing ski masks and wielding submachine guns burst in, grab the corpse, and make their escape. No one is injured, but the question remains: who stole the body, and why? Castle is eager to pursue the case, but Beckett will only let him if he agrees to go away, forever, once it’s over. Castle says he will make her change her mind, but agrees to her terms. As they leave, Ryan pays Esposito; he’d bet that Beckett wouldn’t forgive Castle.

Bigby tells them that Allen played in underground poker games in Chinatown. When he lost his job, poker had become his only source of income, until his luck turned south and his bets escalated. John Allen was deeply in debt to a tattooed Russian. Bigby, trying to help, got him the job with the drug gang. They now know how and why Allen was murdered, but not who did it. Castle realizes that if they can find the poker game, they’ll find their killer. Playing poker with his poker buddies, he points out that several of them had scenes in their books at games like this. Can they hook him up? They try to talk Castle out of the idea; these are unbelievably dangerous people, and the other writers instantly realize that Castle is doing this just to impress Beckett. But Castle is adamant, and finally Stephen J. Cannell agrees to share the information.

The plan is that Castle will wear a wire, and play a bored playboy looking for action while he scouts out the poker game. Beckett, Esposito, and Ryan will be watching and listening from nearby in a van. At the den, Castle sees a bunch of tattooed Russians at the no limit table, and goes over there to play. Explaining that he’s a writer looking to do research, the others mutter a joke in Russian and let him in. Beckett, in the van, is fluent in Russian, and realizes that they’re about to take him for everything he has. Castle narrates the story of his new book about a Russian mobster and poker player. He gambles his victims deep into debt, and then uses his side business as a loan shark to bankrupt them completely. He’s trying to smoke out the killer into revealing something, and to distract the other players. Beckett, watching through the camera on Castle’s wire, notices that one of the players has a prosthetic finger.

Realizing that Castle’s life is in danger, Beckett changes clothes and heads in to save him. Without her pants, her conservative suit coat makes for a very revealing dress. Too much makeup, some changes to her hair, and a Russian accent transforms her into a Russian party girl. Meanwhile, Castle has once again proven to be a fantastic poker player. Instead of being hustled, he’s taken them for everything. The Russian mobster, angry at being beaten and scared that he’s been identified, holds Castle at gunpoint in a side room when Beckett comes in. She gets the drop on the killer and apprehends him just in time to save Castle from a bullet to the head.

Castle goes back to the station. He admits to Beckett that he was wrong, that she was right, and that he’s sorry for hurting her. He agrees to never see her again, but wanted her to know that before he was gone.