Ditto

So-eun, a student at Silla University, eagerly awaits Dong-hee's return from the army. HAM radio is her hobby, and she cherishes the letters she wrote during the war. They meet outside the amateur radio club room, and he thanks her for the letters.

So-eun visits Sun-mi in the hospital and confesses that she is in love with Dong-hee. The hospital setting emphasizes how time and circumstance have kept them apart. This revelation marks the start of their complicated, longing relationship.

That night, So-eun receives a radio call from Ji-in and learns they attend the same university. They plan to meet in front of the school's clock tower. The moment plants a bond between two strangers across the air.

At the appointed time, So-eun waits by an unfinished clock tower in heat and dust, while Ji-in waits by a completed one in heavy rain. They never meet, and the stormy weather becomes a symbol of their growing separation by time. The incident leaves them both puzzled and strangely aware.

That night they argue about why the other did not show up and about the weather. Ji-in realizes they are speaking across years; So-eun confirms she is a junior in 1979 while he is a student in 2000. The truth of their connection gradually sinks in.

During student demonstrations, Dong-hee is injured and So-eun visits him tearfully. She signs her name on his plaster cast, a small act that marks her claim on his life. Ji-in shares snippets from So-eun's future, deepening the connection between them.

Ji-in reveals that his parents attended Silla University at the same time as So-eun and that the plaster cast bears Sun-mi and Dong-hee's names. This shocks So-eun and makes her question what she has really known about her own past. The weight of the discovery unsettles her.

So-eun runs to the hospital to see the sleeping Dong-hee, finding Sun-mi's name now signed on the plaster cast. The moment triggers guilt and a sense that her choices have altered something fundamental. She confides more to Ji-in and begins to reassess her feelings.

In a candid talk with Ji-in, So-eun contemplates her future and the idea of a true destination beyond Dong-hee. She breaks up with him the next day, choosing to follow where her heart and fate seem to lead. The breakup marks a turning point in her life.

On a visit to his parents' country home, Ji-in sees photos and the yearbook that reveal So-eun was in love with his father. The discovery unsettles him and makes him question his own identity. He wonders how this knowledge will affect their future.

Reflecting on the past, Ji-in continues to seek answers about So-eun's life and hopes to learn how she fared in the year 2000. He pieces together the emotional arc of their unlikely bond. The pursuit underscores the idea that destinies may be written across time.

In the year 2000, Ji-in finds So-eun again, now a professor of English at another university. She remains single and seemingly content, though she recognizes him with a quiet, pale memory. He tells her that he once saw her that day, sealing the strange loop between their lives.

The radio ceases to work, and their cross-temporal friendship dissolves. Ji-in accepts his life with Hyeon-ji, and So-eun continues with her career, realizing that Dong-hee was not their destination after all.