Tova is a 70-year-old widow who works as the nighttime cleaning woman at the Sowell Bay Aquarium. She copes with the losses of her husband and teenage son by keeping constantly busy and completing daily crossword puzzles. Fiercely independent, she actively researches moving to a high-end retirement home to avoid becoming a burden to her remaining friends.

Cameron is a 30-year-old man from Modesto who struggles to hold steady employment or maintain personal relationships. Following a sudden breakup, he relies on his childhood friends for shelter before traveling to the Pacific Northwest to track down a wealthy real estate developer he believes to be his absent father. He takes a temporary maintenance job at the Sowell Bay Aquarium to fund his search.

Marcellus is a giant Pacific octopus living in an enclosure at the Sowell Bay Aquarium. Highly observant, he understands human language and regularly escapes his tank at night to hunt for snacks in the facility. He knows he is nearing the end of his natural four-year lifespan and views the aquarium visitors with a mixture of disdain and curiosity.

Ethan is a Scottish expatriate who owns and operates the Shop-Way grocery store in Sowell Bay. He moved to the United States decades ago for a relationship that ultimately failed, choosing to stay and establish roots in the small coastal town. He enjoys chatting with his customers and keeps a protective eye on Tova as she works late hours.

Jeanne is Cameron's aunt, a practical woman who raised him after his mother left. Medical hardships forced her to sell her tidy house and move into a trailer park, but she continues to support Cameron financially when necessary. She frequently chides him for his lack of direction while desperately wanting him to succeed.

Avery owns a paddleboard shop in Sowell Bay and raises her teenage son as a single mother. She is direct, protective of her independence, and unimpressed by Cameron's initial attempts at manipulation. She eventually agrees to teach him how to paddleboard, offering him a glimpse of what a responsible life looks like.

Terry is the director of the Sowell Bay Aquarium. He manages the facility's daily operations, oversees the welfare of the marine life, and relies heavily on Tova's exceptional cleaning skills. He worries constantly about the safety of his exhibits and the liability of slippery floors.

Simon is a wealthy, successful real estate developer based in Seattle. Cameron discovers his name through old high school memorabilia and drives to Washington convinced that Simon owes him years of back child support.

Daphne is Cameron's absent mother. She left him in the care of her sister Jeanne when he was nine years old. Her past actions, old photographs, and connections to Sowell Bay heavily influence Cameron's current decisions.

Erik is Tova's late son. He disappeared on a boat at the age of eighteen, an event officially ruled a suicide. His absence casts a long shadow over Tova's life, dictating her daily routines and her refusal to properly unpack his childhood bedroom.

Will was Tova's husband and Erik's father. He passed away from cancer several years before the events of the story. Tova frequently visits his grave and holds imaginary conversations with him about her daily choices.

Lars is Tova's estranged brother who recently died in a high-end retirement facility called Charter Village. His passing forces Tova to travel to the facility to handle his estate, prompting her to confront her own plans for aging.

Elizabeth is one of Cameron's oldest friends. She is currently pregnant and married to Brad. Her stable, adult life provides a sharp contrast to Cameron's lack of direction, and she allows him to crash at her house temporarily after his eviction.

Brad is Cameron's long-time friend and former bandmate in a local music group called Moth Sausage. He recently stepped away from the band to prepare for fatherhood with his wife Elizabeth, highlighting the growing distance between his maturity and Cameron's stagnation.

Katie is Cameron's girlfriend in Modesto. She reaches her breaking point with Cameron's lies about his employment status, prompting her to throw his belongings out the window and permanently end their relationship.

Janice is a member of the Knit-Wits, a senior women's social group. She frequently checks on Tova, brings her homemade casseroles, and worries about her working a physical cleaning job at her age.

Jessica is a local realtor in Sowell Bay. Cameron manipulates her into providing old address records by playing on her sympathies regarding his broken family. She shares a building with Avery's shop.

Cat is a stray feline that starts visiting Tova's house. Tova feeds the animal leftovers, creating a quiet companionship at home that mirrors her solitary nature.