You follows the life of Joe Goldberg. He works in a bookstore, living a seemingly normal life until a beautiful girl walks through the door. She is the epitome, real-life version of what he wants in a girlfriend, and he quickly becomes obsessed. Having a nice conversation at his store, he catches her name and stalks her, finding her address and spending time outside her house, looking in through her windows. One day, as he is following her, she loses her phone down a subway line, nearly falling into it herself. Thankfully, Joe is there to save her, rendering himself a hero.
Joe steals her phone and uses it to track all the messages she sends to her friends. He then finds out that she is still in contact with her on-and-off ex-boyfriend Benji. Joe believes Benji is bad for Beck, as he sees that he is treating her badly, while he is simultaneously keeping Beck away from him. Hoping to end the fixation she has with him, Joe kills Benji, thus making him disappear from the face of the earth. Their relationship grows, nearing on a real romantic relationship. However, as Beck's friend Peach calls, Beck leaves Joe. Joe kills Peach to remove the distraction. Joe also plans on killing Beck's therapist, so she might start coming to him to talk instead of the man. Before he gets that far, Beck calls him for help.
Peach's body has been found, and the case has been written off as a suicide attempt. Joe comforts her, and their relationship unfolds fully. After a short while though, Beck begins pulling herself back from the relationship. Joe finds her in front of a box filled with things he took from her while stalking her. She accuses him for it, and he locks her in a room for antique books below his bookstore. He finds out that she has been having an affair with her therapist, and Joe confronts her with it, trying to make her say that she loves him and not the therapist. Beck then seduces Joe, letting her out of the box-like room, before she attacks him. Joe is forced to "kill" her. The scene then cuts forward to Joe. He is in his little bookshop, as a new girl comes in. She is just Joe’s type.
