Thomas Whitman, portrayed by Francis X. McCarthy, is a 75-year-old former musician who finds himself in a coma, having battled multi-infarct dementia for years. As he clings to life, his estranged daughter, Gem Whitman, faces a heart-wrenching decision about whether to sign a do not resuscitate order. Meanwhile, in the depths of his mind, Thomas is transported into a vibrant fantasy world where he revisits his childhood as a ten-year-old orphan.
In this dreamscape, young Thomas encounters a girl named Ann at the orphanage and obtains a snow globe featuring a dancing figurine known as "Arabesque." He also becomes friends with a snowman named Mr. White, who flies him through the skies. However, during the exhilarating chase after his father Theodore's airplane, Thomas loses his balance and tumbles into a surreal realm symbolized by a dilapidated roller coaster track, mirroring the fragility of his own memories. As parts of this track disintegrate, a mechanic, mirroring Thomas' real-life doctor Dr. Jansson, expresses frustration about the futility of repairing it.
In a poignant moment, the youthful version of Gem appears, advising they let the track fall apart, paralleling her eventual decision to agree to the DNR order in reality. Thomas soon discovers an even younger iteration of Gem and a 72-year-old Ann, who caution him against Mr. White. Seeking refuge in a "dollhouse," he finds himself and Ann as vibrant members of their band, Whitman, in their 30s. Once more, the elderly Ann warns him of the snowman's malevolent essence, suggesting it contributes to his memory loss.
As Thomas continues his journey through memories, he witnesses both his father and his older self grappling with the loss of their wives, culminating in a tragic scene where Theodore shoots himself. In a parallel moment, the elder Thomas breaks the Arabesque globe, representing his emotional estrangement from his daughter. Throughout this fantastical landscape, he chases after Gem, reflecting their aging progression to modern-day.
In the real world, Gem finds herself at Thomas' home, where she meets Ann, who reveals a painful truth about their shared past. During their time together with their band, Thomas' wife tragically died in a car accident when Gem was just a child. With Thomas often absent, Gem held resentment towards him throughout her life. Ann explains how, on the fateful night of the accident, Thomas had stopped her from overdosing, drawing parallels to the trauma of his father's suicide.
As Gem uncovers incomprehensible notes in a safe, she begins to understand that Thomas became embittered, reflecting the mistakes of his father. This realization leads her to piece together memories that show Thomas did indeed care for her. As she organizes the sheets in his study, an unexpected power failure leads Ann to take Gem to the hospital, further emphasizing the urgency of the situation.
In his dream world, Thomas reconnects with his cherished memories of Gem and confronts Mr. White, who unveils himself as the manifestation of his father. During a thrilling roller coaster ride, Thomas musters the courage to let go of his father's grasp and embarks on a path to cherish his memories with Gem instead. He ultimately completes the ride and awakens from his coma, finding both Gem and Ann by his side. With his final breath, he shares a moment of reconciliation with Gem before passing away.
Upon returning to her father's home, Gem sits at the grand piano. While she plays, a note eludes her, leading her to uncover a brass nameplate wedged within the piano's wires. Its inscription reads "G Em," symbolizing both her name and the chords that Thomas associated with his memories. Notably, Thomas often mentioned that these very chords were fundamental to his recollections and his desire to hear them one last time. Understanding her father's love for her, Gem plays the chords correctly, causing the Arabesque within the globe to spin, marking a heartfelt reconciliation between father and daughter.
