The following version of this book was used to create the guide: Heisey, Monica. Really Good, Actually. HarperCollins Publishers, 2023.

Monica Heisey's novel Really Good, Actually is written from the first person point of view of the protagonist Maggie. The author employs an atypical narrative structure and uses both the past and present tenses. For the sake of clarity, the following summary relies upon the present tense and a linear mode of explanation.

Six hundred and eight days after Maggie and Jon's wedding, Jon moves out. Although their marriage did not last, Maggie and Jon had been together since they were 19 years old. Therefore, in the wake of their separation, Maggie feels disoriented, alone, and unsettled. Although she has a group of close friends, she avoids telling them about what has happened. The end of her relationship with Jon forces her into an unknown that she cannot imagine navigating.

Over the course of the month following Jon's departure, Maggie spends the majority of her time at home alone in her Toronto apartment. She avoids reporting to the office to work with her boss Merris. She typically acts as Merris's research assistant during the summer months, but finds it nearly impossible to return to her normal schedule. Merris is understanding and allows her to work from home. Instead of doing so, however, Maggie primarily occupies herself by surfing the internet, following strangers online, stalking Jon's social media accounts, and binge-watching television shows.

Once Maggie finally tells her friends Clive, Amirah, and the Laurens what has happened, they come over to her apartment to comfort her. They suggest that she sounds depressed, but Maggie resists this label. Amirah then decides to connect her with her colleague Amy, also a divorcée.

When Maggie can no longer afford to live in her apartment alone, Merris invites her to move into her basement studio apartment. The Laurens help her pack and relocate.

Maggie and Amy immediately get along. Maggie particularly admires Amy because she is unafraid of owning her emotions. Per Amy's suggestion, after their night out together, Maggie starts to online date.

Maggie meets a man named Simon at a bar. The two start to see one another regularly over the course of the weeks that follow. Although Maggie does like Simon, she is often withdrawn in his company. She tries to convince herself that she is over Jon and that she is in love with Simon. However, Simon can detect her insincerity and confusion. They ultimately break up.

Maggie attends a therapy session with a therapist named Helen. During the session, they call Jon. Maggie tells him she wants to get back together, but Jon is ready to move on. At the session's end, Helen encourages Maggie to return for future solo sessions.

Maggie invites Merris to accompany her to her friend Emily's wedding. At the wedding, Maggie drinks heavily to quell her heartbreak. When Merris calls a car and tries to get Maggie to go home, Maggie runs away from her. While chasing Maggie down, Merris falls.

While waiting for Merris at the hospital, Amirah confronts Maggie about her recent behavior. She insists that she needs to try hard and do better.

Maggie moves to Kingston to stay with her father for a while. Although she misses her friends and life in Toronto, this time on her own teaches her about herself. Not long before her thirtieth birthday, Amy invites Maggie to move in with her in Toronto. Maggie accepts, grateful for her network of close friends.