Oliver is uncomfortable when Laurel pushes him to investigate Sebastian Blood, the man he backs for mayor of Starling City.
Sebastian Blood visits his mother and after she confesses what she said to Laurel, he kills her.
Flashback: Sara wants Oliver to consider Ivo's offer to give up the serum because he was good to her. She says he's not evil and kept her safe and taught her things on the ship for over a year.
Laurel wants the ADA, Adam, to investigate the murder of Maya, but he refuses.
Oliver reaches out to praise Roy, but doesn't get very far.
Laurel appeals to The Arrow to help with the investigation of Sebastian Blood, but he seems hesitant.
Diggle and Oliver aren't convinced about Blood, but Felicity is easier to believe.
Roy talks with Sin about his new powers and says that he doesn't need Arrow to help him save the city and they set off to find bad guys.
Laurel takes more pills as she continues to doubt herself. The Arrow then shows up and tells her he needs her.
Flashback: Sara and Oliver talk about whether they will ever get home and Sara admits to a secret crush she had on Oliver that lead to her getting grounded after Laurel tipped off Lance about a party she went to so Sara could see Oliver. Shortly thereafter, Laurel and Oliver were a couple.
Laurel Arrow search the Starling City Archive for Sebastian's dad's murder. When Laurel looks inside, it's been emptied.
Roy and Thea are not getting along because he's keeping secrets. Roy decides to use Sin as bait to lure the Starling Slasher and capture their own bad guy.
Oliver goes to Sebastian Blood and asks after Laurel, wondering if they broke up or something. Blood says he will take care of Laurel.
Sin successfully picks up the Slasher and Roy tears the door off of his car and beats the tar out of him, pushing Sin to the ground in the process.
Slade pays Blood a visit, his dad's file in hand. He tells Blood to take care of Laurel. Blood calls in a favor and the police pick up Laurel for drugs in her house that weren't prescribed to her.
Laurel looks like the girl who cried wolf.
Flashback: Sara makes contact with Ivo. She sympathizes with him and he sucks her in by telling her she saved him and the darkness is coming back for him and he needs her to save him again.
Oliver takes Laurel home and tells her that he knows this is not her, that she needs someone to lean on and she disagrees and asks him for a glass of water. He gets knocked out and Laurel is kidnapped by Blood.
Oliver knows where to find Laurel and Arrow finds her. They fight and Laurel shoots the man in the mask, but it's not Blood, it's the policeman, Officer Daily.
Laurel loses her job over the substance abuse problem.
Oliver can't believe he almost thought poorly of Sebastian only because Laurel was his blind spot.
Flashback: Sara tells Ivo that she was once proud to be a part of his research, but now she would rather be dead than continue to be involved.
Arrow meets with Roy again and tells him he has seen the serum before, and wants to train with him. Roy asks when they start.