Someday or One Day (2019) Review: A Song Opens Time

Is Someday or One Day worth watching?

Yes. Someday or One Day is one of the finest romantic dramas to come out of Asia in the last decade, a time-travel love story that is as emotionally precise as it is intricately plotted. Alice Ko and Greg Hsu carry it with performances that make grief and first love feel equally real. The one caveat is that the science-fiction mechanics become knotty in later episodes, and viewers who want every rule explained may need to let a few things go.

What is Someday or One Day about?

In 2019, Huang Yu-hsuan (Alice Ko) is still grieving the boyfriend she lost two years earlier. When a mysterious package brings her an old cassette player and a tape of a 1990s pop song, she finds herself waking up in 1998 inside the body of a shy high-school girl. There she meets a teenage boy who looks exactly like the man she loved, and she has no idea how she got there or what she is supposed to change.

That is only the doorway. Someday or One Day quickly becomes as much a mystery as a romance, with Yu-hsuan piecing together who she is inhabiting, why the past feels so fragile and what connects the two timelines. Patrick Shih completes the central trio as a loyal friend whose own feelings complicate the picture.

The series is a Taiwanese production in Mandarin that aired from 2019 into 2020. This review covers the complete story: one season of 13 episodes, with no loose ends waiting on a renewal.

Two actors, several people each

Much of the show’s power comes from casting that asks its leads to play more than one person. Alice Ko moves between an adult woman hollowed out by loss and a withdrawn teenager with a very different temperament, often signalling the switch with nothing more than posture and the way she holds eye contact. It is a quietly virtuosic performance, and it is the reason the time travel never feels like a gimmick.

Greg Hsu matches her. He has to make two versions of a similar face read as distinct characters, one easy and warm, the other guarded and awkward, and he manages it with remarkable restraint. The chemistry between them is tender rather than showy, built on small moments that grow in meaning once the audience understands what is at stake. It is easy to see why the show turned both into stars across the region.

Music as the machinery of memory

In most dramas a soundtrack sits in the background. Here the central song is part of the plot, the trigger that pulls characters between decades, and the series uses it with such care that each repetition hits harder than the last. The late-1990s setting is lovingly detailed, from school uniforms to cassette culture, and the nostalgia is never merely decorative: it is tied to the feeling of wanting to go back and fix something.

The writing rewards attention. Details planted in early episodes return with new significance, and the show takes genuine risks with structure, letting viewers work out the connections alongside Yu-hsuan rather than spelling everything out.

Where the puzzle gets tangled

The ambition has a cost. By the later episodes the timelines and identities multiply, and the rules governing who can travel where become harder to hold in your head. A second viewing clarifies a great deal, which is a compliment to the design but also a sign that the plotting occasionally outruns the storytelling. None of this dulls the emotional payoff, but it is the one area where the series asks for patience.

Who should watch Someday or One Day?

It is essential for fans of romance and time-travel stories, and a strong entry point for viewers new to Taiwanese television. Thirteen episodes make it a manageable binge, though the mystery works best watched closely rather than in the background. It deals with grief, death and some darker crime elements, so it is more intense than a typical school romance.

Worth adding to the list afterwards:

• Love Alarm, a Korean romance that also uses a science-fiction hook to explore first love.
• When Life Gives You Tangerines for a love story that spans decades and treats memory with similar tenderness.
• Light the Night, another Taiwanese drama that blends period atmosphere with an unfolding mystery.

The verdict

Someday or One Day is a romantic drama with the construction of a thriller and the heart of a love song. Its later puzzle-work can overwhelm, but Alice Ko and Greg Hsu give it a depth that lingers long after the final episode, and it remains the benchmark for time-slip romance.

Rating: 5/5