The episode begins with a 3 ½ year old boy Sam calling 911 and saying that his mom is asleep. His house is located on the system, while he is on the phone. Nick and Olivia arrive at Sam’s doorstep and ask him to open the door. He opens the door and lets them in. Inside they see his mother on the floor with blood on the floor. Olivia asks him what happened, he tells her about his mom and sister fighting about a bad man taking his sister away. Later at the precinct Sam is tucked in by Olivia, the boy’s father has been informed, and his mother has been taken for an MRI, there is a gash in the back of her head. Meanwhile, the boy’s father Jeff Avery comes in. He tells them about his daughter who is 16 and how they can’t get in touch with her because he took her cell phone away, because she was texting at the dinner table.
Jeff says that an alert should be sounded if his daughter has been abducted. Olivia tells him that rather than someone attacking his wife might have fallen, as there are signs of drinking. Olivia and Nick ask Jeff about his daughter, and if she has a boyfriend. Jeff doesn’t know as she blocked him from her Facebook. He gives them, the name of her childhood friend Angela Riva. Later, Angela tells Fin and Casey that, she and Kate the little boys elder sister haven’t been friends since fifth grade. Angela’s mother adds that she had told her daughter to stay away from Kate as she hangs with a bad crowd. Angela defends Kate telling them that she was different lately, and used to spend nights on the computer in the library, really trying to turn her grades around. Outside, Casey tells Fin that it wasn’t probably studying that Kate was doing, but instead chatting with someone she didn’t want her parents to know.
The two then pay the library a visit, to know what Kate has really been doing. They find out that Kate has checked out a website, with heartwarming stories about children born of sperm donation who connect with their biological parents, and their biological brothers and sisters. Later at the precinct Olivia and team wonder about Kate’s whereabouts. Just then Dr. George Huang comes in. He is there to help with the case. He is asked by Olivia about the psychology of donor children. He tells her that donor banks have always maintained donor confidentiality, but they have never thought how it would affect the children. The doctor says it’s not uncommon for these children to want to find out their donors. Meanwhile, Grace, Kate’s mother has been released from the hospital, and ready to be questioned.
Later at Grace’s apartment, she tells Nick that she slipped fell and hit her head. Olivia asks her about Sam telling her that Grace and Kate were fighting about a bad man. Grace denies it, and says it must be Sam’s imagination. She says that she and Kate were fighting about mother daughter stuff. Grace then tells them, after taking a promise that her husband should never know that, Kate was conceived from donor sperm. Kate somehow tracked down the donor online and was about to meet him. Grace tried to stop Kate from doing so. She tells them that she used the same sample to have Kate and Sam. Kate found out when she was searching for old family photographs, and stumbled about a medical card from New York cryogenics. Olivia in the meanwhile, receives an alert that Kate’s debit card was used at a coffee shop and also, receives the address of the place. They see that Kate spent $24 on the coffee, which might mean Kate is not alone. Fin and Casey escort her back to the precinct; she looks around for someone before leaving.
At the precinct Kate is asked about her biological father, and she was with him. She feigns ignorance and says she was with a girlfriend. Meanwhile, Jeff comes in and takes Kate away. In the security cam footage of the coffee shop, the guy talking to Kate is sitting with his back to the camera. Olivia feels the guy is a pro and was possibly trying to avoid detection. Casey then informs the team that Kate isn’t the only one this donor 141 is tracking through the website; there are three other girls too in his radar. They decide to find out something from New York cryogenics. Olivia and Casey pretend to be a lesbian couple who want to have a baby. They tell the lady at the counter that they want sperm from donor 141, as one of their friends has had a great experience with his sperm. She informs them that the bank has run out of donor 141 sperms 5 years ago, as he was very popular.
Casey asks to see the donor’s profile, so they can select a profile similar to his. Later, at the apartment of Ashley Riggs another donor 141, product, Nick is informed that Ashley has met him. She says, this donor Dr. Baker is an amazing man, but he also has told her that no one can know about her, as he has a family of his own. Nick and Fin then come to know that the teenager Ashley is herself a mother. A guy called Joey is the one with whom Ashley had her baby, and he too is a teenager. Joey is shy and sickly, and is bullied by other kids. Ashley’s mother tells them that she never thought she would have to worry about Joey doing such a thing. Fin thinks the father of Ashley’s child might be the donor and not Joey. Later, Nick informs the team that Ashley’s baby’s DNA is being tested to see if it matches with donor 141. George tells the team that the donor might be suffering from GSA (Genetic Sexual Attraction). They then search for the profile described by Ashley, and although the name doesn’t check out they check out for vivo lungs transplant specialist, as the donor claimed he was, and zero in on just 4 doctors in the city.
They then zero in on one man Colin Barnes, who fits the donor’s physical description. They pay Colin a visit. Colin tells Olivia later at the precinct that, he donated on the condition of anonymity, and has never contacted one of his offspring. He is then told by Olivia how the girls told them about him. Just then Colin’s lawyer comes in and tells him to hold his silence. Later, Colin is made to stand in a line up. Meanwhile, Ashley doesn’t recognize Colin from a line up. None of the other girls recognize him either. The team feels the girls might be protecting Colin, as they all like him. Later Kate is told by Olivia that donor 141, was in the lineup. Kate doesn’t believe that. Olivia confirms the fact with Kate that the man, who she met with the other night, is not her biological father. The other girls are questioned one by one, and tell the team how based on similarities to themselves the girls were convinced of the donor being their father.
Meanwhile, Ashley confesses to Nick that her baby is of the donor’s, as they slept together. Each of the girls had sex with him, as they all fell in love with him. The DNA report in the meanwhile, confirms that Colin Barnes is the father of the girls, but Ashley’s baby isn’t his, which means Colin isn’t the culprit. They now try to find out who has a vendetta against Barnes that, he would try to do such a thing, using his name. Meanwhile, Colin’s daughter leaves the house in a huff, as she is outraged by him being a sperm donor. Just then Nick and Olivia come in and tell Colin about someone using his name. Colin tells them about a person named Philip Kelly, who is a fellow surgeon and someone who Colin fired a year ago. Philip was angry about being fired, and might be holding a grudge. Later, when Fin and Casey question Philip, he tells them he is innocent. He then tells them how Colin’s daughter too hates Colin. She was saying the same to someone at Philips party. He doesn’t remember who it was.
Meanwhile, Colin’s daughter is dancing with some man, and complaining about her father. Later, Colin tells the team that her daughter didn’t come back home the previous night. Nick checks her laptop. There is music file on it sent to her by someone. It is the same piece of music which, was played by Colin‘s wife’s boyfriend named Sean, for her in college. She tells them that Sean was at the party that Philip was talking about. Meanwhile, Sean is not to be found anywhere by the team. Meanwhile, it is also discovered that Colin had years ago caught Sean writing the MCATs for someone else, and had blown the whistle. Colin’s wife meanwhile receives a text for Sean, wanting to see her. The message says that if she doesn’t come she would never see her daughter again. The team takes Sean in custody, and he tells the team that Taylor, Colin’s daughter wants to be with him.
Sean tells them that, he felt bad about Sean’s other daughters too, so he did what he did. HE basically thought they were lonely and wanted to be their father. He then addresses Colin’s wife Ann from across the interrogation room glass, and tells her that he wants to see her and will only tell her where Taylor is. He meets Ann, and asks her for one dance, with Colin watching. The two, then slow dances to some music. He then whispers something in Ann’s ears, and she begins shrieking and crying. She comes out and tells Colin that Sean has killed Taylor. They then search for Taylor’s body and based on the clues, finds Taylor actually alive and healthy in a hotel room. She asks for Sean. The team then tells Taylor the truth about Sean. Taylor though isn’t ready to believe that Sean isn’t her father. The episode ends at this point.