So, a once-promising songwriter who has lost his spark, finds himself bedridden with severe gout and driven to suicide. In the quiet of the hospital, he is unexpectedly drawn back to the past when he encounters his childhood love, Ha. But the reunion is short-lived—through a mutual friend, Bing, So learns that Ha has died of cancer. After Ha’s funeral, he meets a girl named Summer, who claims to be Ha’s daughter and asks him to scatter her mother’s cremated ashes in Japan, a final wish that tugs at So’s memory and conscience.
At first, So hesitates, yet his sense of duty—and a stubborn thread of attachment—pull him toward Japan. He reconnects with Summer at a hotel, and Summer’s eager warmth contrasts with So’s lingering reserve. When they share drinks at a pub and Summer plays one of So’s songs on the piano, memories of Ha rush back. They talk about their shared past in Cheung Chau, where a chance meeting in a record shop had drawn So and Ha together over a mutual love of music. Ha would later seek So out in a warehouse at their old school, drawn to his raw, emotional compositions, and the two begin a pattern of frequent conversations where Ha offers feedback and encouragement.
Buoyed by Ha’s influence, So enters a singing contest in the urban district. He performs his own original song, but the judges reject him, eliminating his chance at glory. That very day, life interrupts with a harsher truth: So encounters his father, who is cheating with another woman, and learns his father intends to divorce his mother. Ha’s resolve to confess her own feelings for So is tempered by the looming family upheaval and the possibility that So will soon leave for Australia with his mother.
Heartbreak flashes across Ha’s face, and her grandmother consoles her with a crystal necklace capable of transporting a person through time and space. With a single wish, Ha travels forward into the future, ending up in the hospital where her future self lies. The future Ha, knowing she is dying, asks Ha to seek So for her sake and reveals a startling twist: Summer is Ha herself, time-traveling from the past.
Back in the present, Summer slips into So’s room and sends his unfinished song to a producer on his behalf. At first, So is angry, but Summer’s apology and a fragile openness begin to thaw his reserve. They scatter Ha’s ashes together, and So, moved by the moment, contemplates quitting music—yet Summer’s insistence and a performance of a song about chasing dreams rekindle his drive. Then a revelation changes everything: Summer is actually Ha from the past, and Ha steps away through a shrine, leaving So to process the encounter.
So returns to Hong Kong and, with Bing’s help, tracks down Ha’s real daughter. The daughter lends him her mother’s crystal necklace, enabling So to make another wish and step back in time. He finds the younger versions of himself and Ha at the beach, playing with friends. Ha recognizes the older So and invites him into a private conversation with the younger Ha. The older So shares the incomplete song with the younger So, who, unaware of his future fame, helps improvise the missing final section. The two Sos—one from the present and one from the past—discuss their shared dreams and vow to try to shape a better future.
Upon returning to the present, So reaches out to Ha, who reveals that she has survived thanks to alternative treatments. The couple’s bond is finally repaired in a quiet, poignant reunion at their alma mater’s warehouse, where So performs the now-completed song for Ha. In the end, the music, the time-traveling echoes of their past, and the stubborn hope that binds them together affirm that love can endure—and perhaps even redefine what is possible for both of them.
