The episode begins with a family enjoying the snow on Christmas Eve, when they see a Santa falling towards them from the skies. Santa lands on the snow with a huge thud. The kid screams. Meanwhile, Castle and Alexis are decorating the tree. Alexis and Martha are having their own plans and Castle is upset that they aren’t following the family tradition. He wants to spend one evening with them and they cant manage that. At the crime scene, Castle is complaining to Kate. He hopes that Kate is with him. She says that she will be if she has no work. Ryan and Castle are upset to see a dead Santa while Kate reminds them that there is no real Santa.
Lainey tells them that there is an ID; Kris Kingle. He doesn’t seem to have fallen from very high altitude as there are no severe frost bites. The family who saw Santa hurling down, did not see a plane. Kate asks Ryan to check with air traffic control. Kate checks the body and says that he is wearing boots from a leather shop at Queens. They feel that they could get his real name from the shoe store. Gates tells the team that air traffic control don’t maintain a log for charter flights who maintain an altitude of 1300 feet. So, then there is no way air traffic control could be of any help. There is a red paint chip found on the body and castle feels it is from Santa’s sleigh. The team learns from the boot store that Santa’s real name is Edmund Smith.
Esposito goes to the morgue to get some more results and he flirts with Lainey, hoping to spend Christmas with her. But she tells him that she has plans and she doesn’t want them to be a sad, desperate holiday hook up. But later if he still wants to, he could give her a call. Castle and Kate go to Edmund’s house but no one answers the door. The neighbors have a spare key and they help them enter the house. They tell the detectives that Ed was a professional Santa and did his job very seriously. Castle sees a clock on the table which starts making noise the moment he touches it. There is a lot of Santa stuff in the house. The neighbor then tells Kate that Ed did not have many enemies but last week they saw a man pounding on Ed’s door and saying a lot of cuss words.
Tim, the neighbor, points out to a photo of a man standing next to his plane; and tells them that this was the guy who threatened to kill Ed. They then learn that the plane is registered to a guy named David Dunne. He has priors too. Ryan gives them an address where they can find David; it is a Santa school. David tells them that he was distributing gifts to kids and that he has flown his plane over a week. He tells him that he was pissed at Ed as he had stolen his gig. And Ed was chosen as Santa this year. So, David was upset, had few drinks and said whatever; but he did not mean anything. Ryan confirms David’s alibi. And also, that his Cessna was in the hanger for over a month now. Ryan says that Ed’s agency said that he did not have any gigs last night. So, why was he wearing his suit? So this has to do with Ed’s past.
Esposito arrives with a picture of James Edmund Smith from five years ago; he was an equity manager. And that to a big one! On the night he died, he withdrew 2k from his ATM; but that money wasn’t found on him. Ryan arrives and tells them that the last call he made was to his ex-wife. They bring her in. she tells them that he had come to visit her to apologize to her as five years ago he walked out on her without saying a word. She tells them that their marriage was good and then on Christmas Eve, he walked out. He wanted to apologize. She points out that Ed was very nervous and said that he wanted to say a sorry before anything happened to him. She then saw him leave in a cab through the window and saw a bike following him.
Esposito sees Jenny’s gift; a kinky Santa suit and he makes fun of Ryan. Later, Ryan tells Castle and Kate that Ed was up against some company who was cheating a lot of people and that a lot of them had lost their homes. This was a class action suit and Ed begged the lawyer not to drop the case and that he would try to help. Help how, he did not say! Kate wants Ryan to check with the Fraud Department about the Suncove, the company Ed was fighting against. Castle asks Kate to spend Christmas with him and she tells him that she has to work as they are short staffed. He is upset. Esposito arrives and tells Kate that Ed took a cab to a small airfield in Jersey. But Ed made the cabbie wait and they came back and went to Long Island City. The go to the airfield and see a cherry red color helicopter.
The locks are tampered with and there is fresh blood on the seat. Looks like they found their crime scene! This helicopter belongs to a guy named Chuck; but he is vacationing in Hawaii. They talk to the manager and learn that anybody can access the airfield and it is really easy to fly an R44. Kate asks Ryan to check all the helipads. At home, Castle learns that Alexis is spending the Eve with her new boyfriend. At the precinct, Castle learns that Kate volunteered for the Christmas shift. He is upset. Kate and Ryan work on the helipads and they figure out that Ed was in the case Commerce building. Kate and Castle go that building and they learn that there has been a heist and that Ed was their Santa at their party.
So, their Santa was a little naughty than nice! He stole a clock and nothing else. This clock is worth around 30k and this is approximately the amount he needed for the case. Esposito tells them that CC had booked another Santa but then the agency got a call saying that they had cancelled the Santa they booked. But actually it wasn’t the agency calling and so when Ed arrived at the party, no one recognized him. So, how did he know that the clock was there and why use a helicopter to steal it? Kate asks Esposito to keep an eye on all pawn shops. Castle confronts Kate about her volunteering for work. She tells him that Christmas reminds her about the time she spent with her mother and that year it seemed like they had put Christmas away forever.
Keeping a watch on the families that are celebrating, is her tradition; she wants it to be that way. Ryan is at CC and he tells Kate that there was a security guard on the roof who was smoking and he told Ryan that there was a lot of debris on the roof; looked like someone was waiting for someone. There is a can of pipe tobacco. And who smokes a pipe? David Dunne. They arrest David. The stolen clock is found in David’s house but David did not know its worth. He admits that he was a getaway flier but he did not kill Ed. Ed had asked him how much weight the helicopter could carry. He tells them that Ed paid him 2k and so he did not question him. He said that Ed came running with a clock in his hand and someone was shooting at him. And later he saw that Ed was dead.
This means the killer is at the party. Esposito finds out from the elevator footage that the neighbor kid, Tim was at the party. Gates arrives and tells the team that Ed was the reason Tim’s life was destroyed and moving out of the house to stay next to Tim’s was an act of redemption. Ed was the authorized signatory of Suncove. They go to Tim’s house. Time tells them that Ed had told him who he really was; he wanted to kill him at first, but Ed wanted Tim’s help to break open into CC to steal the files which would help them in their lawsuit. It was proof of everything that went down the years. That is why Tim was at the party. Kate and Castle go to CC. Kate talks to Mr. Case who owns the company.
He was Ed’s business associate at Suncove, where they forged documents pushing people in a mortgage they could never pay and then sell them off to investors. The watch that was stolen belonged to Tim’s family which they had pawned to pay their mortgage and Suncove kept it. And now since it was in CC before it was stolen, this connects Case to Suncove. Case tells Kate he did not kill Ed, but he knows who did; Ed’s ex-wife. She is called in once again. Ed’s law suit and those files that he was going to steal would completely expose Suncove and she would lose everything she had after the divorce.
Ed had visited her to tell what he was about to do. So she came to CC and killed him. Case closed. At home, Castle is happy that Alexis and his mother cancelled their plans for him, but now he thinks he needs to be with Kate. But then he is shocked to see Kate at his door. They both planned to change their traditions. Esposito takes that clock to Tim’s house to return it to the rightful owners. That is why Ed stole the clock from CC. Tim’s mother is very happy and she invites him for dinner. The episode ends.