Nozomi was a young girl confined to a hospital bed by a serious, prolonged illness. Despite her mother's constant care and companionship, she often felt lonely and bored. She spent her days knitting mittens, scarves, and leg warmers while writing in her diary, expressing wishes to experience life outside like other children.

Observing from her window, she became captivated by a young boy walking energetically to school each day, drawn to his cheerful smile and lively movements. Without knowing his identity or personality, she developed an idealized affection for him. Her diary entries detailed her longing to meet him, her curiosity about his name and relationship status, and her hope for a single date. She specifically knitted a muffler scarf, wool hat, mittens, leg warmers, and began a sweater intended for him.

Tragically, she passed away on Christmas Eve before completing the sweater or fulfilling her wish. Her mother discovered the diary, titled the Diary of Dream, revealing Nozomi's unfulfilled desires. To help her daughter's spirit find peace, her mother entrusted the diary to Sakura, a shrine maiden.

Nozomi's spirit lingered on earth as a ghost due to her unresolved wishes. Sakura arranged a meeting between her spirit and the boy she had watched, Ataru Moroboshi. During their encounter, Nozomi presented the hand-knitted items and shared her story. Touched by her sincerity, Ataru wore all the knitted clothing despite the scorching summer weather. Accompanied by Lum, Sakura, and Cherry, they embarked on a date: watching a movie, riding a roller coaster at an amusement park, and eating lunch at a diner.

After these activities, her spirit remained. Reviewing the diary's final pages revealed her deepest unfulfilled wish: to walk arm-in-arm with Ataru through falling snow while he wore the sweater she had knitted. Achieving real snow in summer proved impossible. As a substitute, while watching fireworks illuminate the night sky, she experienced a moment of beauty that allowed her spirit to pass on. In her final moments, she expressed joy at holding Ataru's arm, mistaking the fireworks' brilliance for snow and stating her happiness that the experience transcended a dream.

Physically, she appeared as a pale young girl with brown hair styled in braided pigtails, wearing a light-blue nightgown and pink wooly slippers. Her personality was characterized as kind, sensible, and gentle. Her story centered on themes of unfulfilled longing and the resolution needed for spiritual peace.