Dexter wakes up in bed with Hannah.When she wakes up, Dexter thinks he should see Dr. Vogel after what happened to Zach. He tells Hannah to stay hidden but she has to go out to get money from Arlene now that her alias has been compromised. They both say they love each other and Dexter leaves to meet up with Vogel at Zach's office.
At Zach's office, Dexter shows Vogel the song that was playing when he found Zach. She thinks that the killer is trying to send a message to Vogel and Dexter but she doesn't know what it is. Vogel tells him to remain focused and he says he is. Dexter finds some hair and blood underneath a desk. Vogel says that Dexter's desire to exact revenge on Zach's killer will make him lose focus. He admits that he is trying to make a life with Hannah and Vogel states that he has a depth of emotion she never thought possible. He promises to kill the brain surgeon and then focus on a possible life with Hannah. Dexter believes that Vogel underestimates his chance at having a full emotional life.
Deputy Marshall Clayton works with Jacob Elway to find information on Hannah McKay. Elway asks to be part of the investigation but Cooper says he won't be allowed but will be paid when she is caught.
Angel meets Deb at a coffee stand and says she should rejoin the force. Deb is there to meet with Quinn. He wants her to look into Zach Hamilton for him. Tom Matthews has told him not to look further into anyone in that influential family so he is hoping Deb can do it for him.
Deb visits the police station to ask Dexter what he has been doing with Zach. Dexter tells her that Zach is dead but no one else knows. Deb thinks about rejoining the police but she thinks it will just lead her into another messed-up situation. She leaves Dexter's office and he continues his work. He finds the blood from Zach's office has a familial match to Dr. Vogel.
Dexter confronts Vogel and says that the brain surgeon serial killer is related to her. She has no family so this can't be possible. She did have two sons but one was found drowned and her older son, Daniel, was the killer. The desire to help Daniel lead her into psychiatry. She wasn't able to treat him so she put him into a mental institute in England, where he died three years later in a fire. Dexter suggests that her son faked his own death and is now the brain surgeon.
Dexter runs a photo of Daniel through age-progression software and discovers that he looks like Cassie's boyfriend, Oliver. He brings up a current picture of Oliver and the software finds that Oliver is a grownup Daniel. Dexter's research is interrupted by Angel, who brings Clayton into his office. Clayton asks Dexter if he has seen Hannah. Angel will have cops at Dexter's apartment and following Harrison to keep them safe from Hannah.
Dexter calls Hannah to tell her not to leave to avoid being caught by cops. He volunteers to drive her to Arlene's himself when he is off work.
At dinner with Deb, Quinn tells her that he needs to solve these murders to prove that he is a good cop. Quinn says that it's hard to talk to Jamie about Cassie's murder, and Deb says that she will ask for him. She thinks it will be fun to pretend to be a cop again.
At Arlene's, she asks if Dexter and Hannah are back together again. She hands a suitcase to Hannah when Dexter notices Clayton is outside. He tells Hannah to hide while he handles him. Clayton asks Arlene a lot of questions about money that she can't answer and Dexter steps in and says that they are dating and he is the one who helps with money. Clayton is clearly skeptical but leaves anyway.
Deb shows up at Dexter's apartment to speak with Jamie. She finds out about Oliver and that he was really clingy. He had planned a trip to the Bahamas with her after dating for only a few weeks. She calls Quinn to tell him they need to focus on Oliver.
Dexter leaves Arlene's with Hannah and he suggests that Hannah may have to stay at Deb's apartment for awhile.
Deb and Quinn visit Oliver to ask him some questions about where he was at the time of the murder. Oliver says he is really busy with work and fully booked for the next few weeks. Deb asks how that is true if he had a trip to the Bahamas planned. Oliver attributes the trip to Cassie and says it probably wouldn't have been possible anyway with all the work he has. Outside his apartment, Deb tells Quinn that Oliver lied to them. Jamie said the vacation was all Oliver's idea in the hopes that Cassie wouldn't dump him. Quinn says that it's nice to be working together again and kisses Deb. She is speechless and after he apologizes she tells him to just pretend it didn't happen.
Deb returns home to find Hannah and Dexter in her apartment. Dexter needs a place for Hannah to stay, somewhere safe from the federal marshal. Deb isn't too happy about it but Dexter says it will only be for a few nights. Deb says that he should also be thankful that she got Quinn off of Zach and focused onto Oliver. Dexter warns Deb that Oliver is dangerous.
Dexter thinks that Quinn and Deb may have spooked Oliver so he needs to act fast. He plans on killing Oliver in his apartment that night but Oliver has already moved out. He does find some DNA to compare against the hair found in Zach's office.
At Dexter's place, Harrison says he misses Hannah and wishes she could be his mom. Dexter receives the DNA results that confirm that Oliver is Vogel's son. He brings his findings to Vogel. Dexter will kill him but Vogel isn't sure she wants him to do that. She hopes that she has a second chance with Oliver. Vogel suggests that her son may be found at a cafe they frequented when he was young. Dexter tells her to write an entry in her journal in the hopes that Oliver is watching her computer usage. Dexter feels bad about lying to Vogel but it's the only way he can find Oliver.
Dexter tells Hannah that he will kill Oliver, even if he must go against Vogel's wishes. Hannah wants to be with Dexter but there is no way she can have a normal life in Miami. She suggests for Dexter and Harrison to move to Argentina with her. He thinks it over and agrees.
Tom Matthews asks Angel if there has been any news on Zach Hamilton. Deb waits in Angel's office for him. He welcomes her back to the homicide unit and she says it's all happening so fast and needs some time to think about it. He doesn't understand but tells her to take all the time she needs. On her way out of the station she sees Quinn. He says that Oliver cleared out of his apartment but at least that means they are on the right track.
Back at her apartment, Hannah asks Deb if she is rejoining the force. Deb asks how she could possibly do that with a serial killer brother and another serial killer hiding in her house. Deb surprises herself by eating food that Hannah made.
Clayton shows up at Dexter's and tells him that the Hannah threat may be gone. He sees Harrison drawing a picture and asks who the blonde woman is. Dexter worries that he will say it's Hannah but Harrison replies that it's his mother. Dexter says that he thinks Harrison draws pictures to feel closer to his dead mother.
Jacob confronts Deb about Hannah. He thinks she is withholding information from him and tells her that if she doesn't want money he can give her office space to someone who cares.
Dexter visits Vogel's office and spikes her tea when she isn't looking. They clarify their plans to bring Oliver to a mental institute. Vogel is excited about meeting her son again but she passes out from Dexter's sedative.
Oliver waits inside the cafe for Vogel but she never shows up. He finally leaves and Dexter follows him away. As Oliver drives away he stares directly at Dexter. He returns to his car to find his car tires slashed. He worries that Oliver went to Vogel's house by himself. Dexter meets Vogel at her house but Oliver hasn't showed up. Dexter promises to take care of Oliver and move away with Harrison and Hannah. Dexter leaves Vogel's apartment but inside Oliver joins her for breakfast.