Actors Do Kyung-soo and Won Jin-ah embark on a magical first love.

The film Secret That Cannot Be Told is a fantasy romance about a man and a woman who accidentally meet in a campus practice room where the secret of time lies hidden.

The main trailer was released on the 3rd, showcasing Yoo Jun (played by Do Kyung-soo) performing on the piano. He pours his heart into gifting sheet music to Jeong-a (played by Won Jin-ah).

The movie captures the innocence of first love. Lines such as "Our meeting is a miracle," and "I'll cross time to meet you," follow their destined first encounter.

Moments of heartbreak are also revealed. Jeong-a's secrets continue to grow, and the two repeatedly miss each other. Their failed meetings naturally lead to misunderstandings.

Further complicating matters, In-hee (played by Shin Ye-eun) misinterprets Yoo Jun's feelings. Their frequent eye contact and his sudden confession deeply wound Jeong-a.

The story raises curiosity about the first love the two will unfold. Yoo Jun expresses his sincerity, saying, "I don't care what your secret is. Just don't disappear again."

A production representative said, "Moments of magical love are accompanied by beautiful piano melodies. This winter, it's set to touch the hearts of audiences."

Meanwhile, Secret That Cannot Be Told is set to open on the 28th.