Ava is an illustrator and ceramicist from Topeka, Kansas, who has struggled with lifelong anxiety. She relies on her art and her dog, PJ, to help manage her emotions and stay grounded. Deeply caring but naturally shy, she sets out on a cross-country journey to locate her sister at an experimental grief-treatment center.

Sasha is a friendly, extroverted occupational therapist from Boston. She is navigating intense grief and guilt following the tragic death of her fiancé, Dean, which occurred just before they were supposed to be married. Hoping to bypass the painful early stages of her mourning, she travels toward the Poppy Fields seeking their experimental sleep treatment.

Ray is a physically fit, capable firefighter who exudes natural leadership. Raised by an emotionally distant father who equated stoicism with masculinity, Ray has difficulty processing complex emotions or asking for help. He embarks on a journey to the Poppy Fields searching for answers and closure after his brother's recent death.

Ellis is a brilliant, driven scientist and the mastermind behind the Poppy Fields' experimental sleep treatment. She prioritizes her research and the public good over personal relationships, leading to a solitary existence and distance from her family. Despite her ambition, she possesses a strong ethical compass and insists on offering her treatment free of charge.

Sky is an eighteen-year-old recent high school graduate traveling across the American Southwest. Raised by free-spirited parents, she embraces a nomadic lifestyle and deliberately avoids making concrete plans for her future. Despite her youth, she possesses an observational wisdom that helps her new travel companions process their own struggles.

Johnny is Ray's deceased brother and a former paramedic. Like Ray, he was raised to suppress his emotions, but he eventually demonstrated emotional maturity by seeking help for his grief at the Poppy Fields. His legacy deeply influences Ray's understanding of vulnerability and healing.

Granny Mae was the loving and supportive primary caretaker for Ava and Ellis after their parents died. She tailored her parenting to each girl's distinct needs, nurturing Ava's artistic talents and encouraging Ellis's intellectual ambitions.

Dean was Sasha's fiancé and former next-door neighbor, a children's piano teacher who also performed his own shows. His sudden death in a drunk driving accident leaves Sasha grappling with profound grief.

PJ is Ava's small, beloved dog, named after a famous nineteenth-century dolphin known for guiding ships through storms. He serves as a vital source of comfort and emotional support for Ava during her travels.

Donna is the pragmatic proprietress of a local bar near the secret facility. Having undergone the sleep treatment herself to cope with her husband's death, she offers valuable perspective to the travelers about the nature of grief.

Flynn is a member of the Poppy Fields leadership team who pushes for the facility's expansion. Unlike Ellis, he envisions shifting the startup to a for-profit model, creating ideological friction within the organization.

Yasmin is one of the original scientists who agreed to join Ellis's startup. She remains a loyal and steady presence on the Poppy Fields staff, helping to manage operations and navigate public scrutiny.

Peter is Sasha's ex-boyfriend from college. As a fellow Asian American, he understood Sasha's experiences in a way that left a lasting impression on her, even after they parted ways.