Thanksgiving is around the corner. Castle tells Beckett that his family has a tradition of dressing-up in costumes on the day. A man collapses and dies in a Church because of multiple-gun wounds. Before he dies, he hands over a baby to the priest.

Cameron Ducane is the name of the victim and he worked for a car driving service. In addition to solving the murder mystery, the 12th precinct team also has to find the baby's parents. The victim's wife has no clue about the baby and denies that her husband was having any affair. The baby has no link to the dead man.

Castle takes over the responsibility of the baby, claiming to be the baby whisperer. Beckett does not hold the baby and tells Castle that she is not a baby person. Ryan holds the baby to see how it feels in real as he is soon going to become a father. The baby starts crying when Ryan holds him, while it is all happy in Castle's hands.

Beckett and Castle visit the victim's workplace. There Ducane's boss tells them that Ducane was a good man. However, Ducane had a heated argument with someone a few days before his death. The boss mentions that the man had a big tattoo on his hand. The tattoo leads the NYDP team to Jimmy Wolfinsky. The man was released on parole, two weeks ago. He was caught for a bank robbery, seven years ago. Ducane was his partner in the crime who was never caught. Wolfinsky tells Beckett that he was seeking help from Ducane to get a job. He had a heated argument with Ducane because he did not help.

Castle and Beckett take the baby home as a foster home could not be arranged, as it is the Thanksgiving week. Castle and Beckett work like a team to change the diaper of the baby. The next morning, they are completely exhausted as the baby keeps them awake the whole night. Beckett tells Castle that when it is time, there is no way she will let him take care of the baby all alone. Beckett's words please Castle as he had to take care of Alexis all alone.

Tracking the GPS system installed on limo that Ducane drove, the investigating team discover that Ducane was driving to Colfax building and from there he used to go to Alphabet city through different routes. He was planning a get-away. At the building, the head security man tells Castle and Beckett that no one reported any robbery or anything missing. Also, the security cameras did not record anything.

The GPS system also leads Beckett and Castle to an abandoned building. There they find blood marks and diaper. There is also the hint that a scuffle has taken place. However, there are no finger prints. The NYPD team later checks the garbage drums to find garbage of the house, which may provide them a clue. In one of the bags, they find the diapers of the baby, ping pong balls, a lotto ticket and a wine preserving kit.

In the episode, Ryan keeps checking on Lotto results, hoping to become instant rich before the birth of his baby. Ryan switches on the T.V at the 12th precinct to find the winning lotto numbers of a Pay T.V. station lotto program. He has purchased a number of tickets of that. He distributes them to his colleagues so that they can check the numbers for him. However, it is the ticket found from the garbage that contains all the winning numbers.

Castle is able to see the link and the T.V station is located in Colfax building. Ducane was involved in the fixing of the lotto result. He and his friends had doctored the balls. The new finding and questioning of the boss at the T.V station lead them to lotto result announcer, Miranda. She tells them about the kidnapping of her baby and her husband. She was asked to keep quiet and do as asked otherwise they would have killed the husband and the baby.

Ducane's boss and the head of security were involved in the crime. Ducane tried to save Miranda's husband and baby when he realised that his boss intends to kill them once the job done. Ducane managed to only save the baby and got shot. However, Beckett and her team saves Miranda's husband before the culprits could silence him for ever.

Beckett arrives to the Thanksgiving dinner wearing a costume. Castle tells her that it was one of his jokes and his family has no such tradition. Beckett says that she knew about that and hands him his costume to wear.