In the novel, Remarkably Bright Creatures, the protagonist, Marcellus, is a captive octopus living in Sowell Bay Aquarium. With just over 161 days left in his life, Marcellus seeks to make the most of his remaining time and possibly even make friends. Along the way, he meets Tova, a friendly 70-year-old widow who works as a night-shift janitor at the aquarium. Tova's cheerful demeanor masks the pain of losing loved ones, and her work helps her cope with grief.

The debut novel by Shelby van Pelt delves into themes such as mystery, grief, the fear of death, aging, loneliness, and even a hint of romance. The story is told in straightforward prose with descriptive writing that captures the magical realism of the novel. Marcellus's mischievous personality adds a touch of humor to the story, making it an enjoyable read.

While the plot may be predictable, the book still manages to be a delightful and engaging read. However, it's worth noting that there may be some trigger warnings that readers should be aware of before diving in.