The following version of this book was used to create the guide: Hazelwood, Ali. Love on the Brain. Penguin Random House LLC, 2022.

Ali Hazelwood's novel Love on the Brain is told from the first person point of view of the main character Bee Königswasser. The novel is written in the present tense, and follows a largely linear plot structure. The following summary adheres to a similar mode of explanation.

Bee Königswasser lives and works in Bethesda, Virginia. She lives alone and works for the National Institutes of Health. Although Bee loves science and loves working, she feels stunted by her life in Bethesda. Therefore, Bee is thrilled when she learns that NASA has chosen her to co-lead their distinguished neuroscience research project called BLINK. The only negative part of this opportunity is that Bee will have to collaborate with her former graduate school classmate and arch nemesis Levi Ward.

Bee travels from Bethesda to Houston to start work with NASA. Her research assistant Rocío accompanies her. On the flight, Bee tweets on her @WhatWouldMarieDo Twitter account. She runs this account under an alias, and tells no one she is associated with it. Since its creation, WWMD has gained followers and attention. It has also become a community for Bee. The followers particularly share their difficult experiences as women working in STEM.

When Bee starts at NASA, she is frustrated to discover that none of her equipment has arrived. She immediately blames Levi, who seems to be treating her with the same disdain. Finally, tired of his petty emotional games, Bee confronts Levi. Not long later, she overhears him advocating for her with their boss, Boris. Bee is even more surprised, when Levi explains the complicated politics behind the BLINK project. Despite their earlier disagreements, together, the colleagues concoct a way to convince Bee to save BLINK. They show him that another company is working on a competitive model of the space helmet they are creating. Boris agrees to let them keep working.

One night, while Bee is running in the cemetery, she discovers that she is locked in. She calls Levi, who comes to her rescue. Because she is locked out of her apartment, Levi invites her to spend the night at his home. Bee is surprised by his hospitality.

Boris sends Bee and Levi to a neuroscience conference in New Orleans to investigate BLINK's competition. On the drive there, the two share intimate details from their personal lives. Not long after their arrival, Bee then runs into her ex-best friend Annie and ex-fiancé Tim. When she passes out, Levi carries her to safety. In his hotel room, Bee reveals the truth. She explains that Annie and Tim betrayed her by sleeping together shortly before her wedding. Levi is shocked and horrified.

For the rest of the weekend, the colleagues continue spending time together. They learn more about each other and grow closer. When they return home, they work out a new advancement for BLINK. Excited by their achievement, they hug and kiss.

Over the course of the following weeks, Bee and Levi continue seeing each other. Levi reveals that he has been in love with Bee since they first met. Bee realizes she cares for him, too. However, when the colleagues' BLINK demonstration goes awry, portending the death of the project, Bee says she is breaking up with Levi and leaving Houston. Despite Levi's pleas, Bee will not change her mind.

Later that same night, Bee discovers that someone has been breaking into her office and hacking her accounts. She learns that one of her other colleagues, Guy, has been trying to sabotage her. When Guy appears and threatens her life, Levi arrives and saves her.

Despite her fears of commitment and abandonment, Bee realizes that she loves Levi. She tells him she is willing to try building a future together.