Kang Shin Woo hasn't gotten over his high school crush, even ten years after graduation. He is given another shot at love when he travels back in time and becomes his own teacher.

As the sports festival approaches, Shin Woo does everything in his power to force his younger self into Na Hee's life.

Younger Shin-woo decides to tell Ji-soo how he feels about her and ask her out. His heart trembles as he walks toward her. He confesses his love to Ji-soo but she tells him that she likes someone else.

The school catches on fire and older Shin-woo and Ji-soo are locked in the classroom. Ji-soo feels jittery about him, however older Shin-woo has concerns about Ji-soo.

With all of his business wrapped up, the older Shin Woo decides it's time to head back to the future.

Shin-woo awakens in the present day and, as soon as he realises that his journey wasn't just a mere dream, is confused.