Spencer visits his mother and tells her what he saw. He asks if William did something to Riley. She says no, begins to freak out and starts slapping her own head. A nurse hears her, walks in and injects her with a sedative. As she is calming down, she tells Spencer that he could have been the victim.

Spencer and Derek walk to the police station and see Riley's dad, Lou, walk out. They wonder what he is doing there. Spencer tells Hyde that he wants to bring his father in for questioning. Hyde tells Spencer to go back to his hotel room and have a couple of drinks by the pool. Spencer is about to walk out, but Derek convinces Hyde to bring in William.

Garcia calls Derek and tells him that the person from the file that Spencer received, Gary Michaels, has a history of lewd behavior and trespassing in a nursery school. She says that he has no record for any activity in years. Derek tells her to keep looking. JJ grabs her abdomen and Garcia notices her pain. Jordan tells Garcia that JJ has been wincing all day. JJ says that she is not due for 3 weeks. Garcia thinks that she is about to give birth and takes her to the hospital.

Spencer, Derek and David watch as William is brought to the interrogation room. He tries to figure out who slipped him Michaels' file. He remembers how resistant Detective Hyde was. He thinks back at how Hyde knew which hotel he was staying. He says that he never told Hyde which hotel he was staying at.

Spencer sits down with his father and asks how he got blood on the clothes that he was burning in 1984. William says that he wants a lawyer. Spencer tells him that he doesn't need a lawyer if he has nothing to hide. William changes the subject and tells Spencer that he is proud of him and his choice to help people. Spencer asks him to tell him the truth. William says that he didn't kill Riley, but he knows who did. Spencer says Gary Michaels. William says yes.

Jordan calls the team and tells them that they found that Gary Michaels is dead. She explains that Gary was murdered and his body was found in a construction site outside of Nevada. She tells them that he was beaten with a pipe or a bat.

The team speak to the station captain. He wonders why the FBI is spending so much time investigating a dead pervert. They find that a pair of broken glasses were found on the scene with a fingerprint. The fingerprint was never processed or identified. Derek tells Spencer that if they find that the print belongs to his dad, he will be put away for a long time. Later, Derek gets a call from the lab. They inform him that they have a match on the print. Derek hangs up and tells Spencer that they will have to get an arrest warrant, but not for his dad.

The team pull up to Lou's construction site. Detective Hyde pulls up and tells them that Lou is his friend and he wants to arrest him. Spencer tells Hyde that he knows that he slipped him Gary's file. Spencer accuses Hyde of not looking for Gary Michaels' killer. Hyde arrest Lou then loads him into the FBI's car to be taken away.

Lou is brought in for questioning. They ask how he knew that Gary was Riley's killer. He says that Gary approached another kid in the neighborhood. He says that he was told by a concerned parent. Spencer remembers being approached by Gary when he was a kid. Spencer asks Lou who told him. Detective Hyde enters the room and Spencer tells him not to interfere. Spencer's mom pushes into the room and says that she told Lou.

Diana, Spencer's mom, tells them that she saw Gary play chess with Spencer. She says that she knew that he was a child molester from the looks he gave Spencer. She told Lou, then two months later, Lou called her to meet him. She went for a ride in his truck where she pointed out Gary putting his trash out in front of his house. Lou told her that Gary has a history of doing bad things to kids. Lou told Diana to leave, but she just sat there as he got out of the truck, grabbed a bat from the back, and entered Gary's house. After a while, Diana entered the house and found Lou standing over Gary's dead body. She ran to Lou then slipped and fell on a puddle of blood. She went back home where William took her clothes and burned them in the morning. William tells Spencer that after that incident, everything changed. He says that he tried to work it out, but couldn't. Spencer tells his dad that he is sorry about his accusations. The team wraps up then takes a flight back home.

Spencer arrives and visits JJ at the hospital. He is introduced to Henry, her baby boy. JJ asks Spencer to hold Henry. JJ asks Spencer if he would like to be his godfather. She says that it is his and Garcia's responsibility to make sure that Henry gets into Yale if they pass away. Spencer holds Henry and tells him that he will get him into Cal Tech instead.