Nak-young, a married university professor, is taken by his friend Dal-soo to a lakeside villa, where he reunites with Nan-shim, a former student, and falls in love with her. Nak-young is invited to give a lecture in Busan, and Nan-shim accompanies him. They embark on a brief but happy journey on a romantic train. Upon returning to Seoul, Nan-shim discovers she has an incurable illness. She leaves her final will to Nak-young before passing away.