Singer Hyeon Seok develops problems with his hearing (Menieres syndrome) and has to stop his recordings. He notices a picture of Hokkaido in a magazine and decides to travel there. He eventually arrives in a a small village in Hokkaido for rest. While there, he reminisces about the old days. The owner of the inn offers him a Japanese meal. There he meets a bright cheerful girl named Megumi.
Love comes in all flavors. Secret Ingredient is the story of a Korean man who gives up his entire luxurious life in Seoul in search of his childhood girlfriend, someone he’s never forgotten all these years, in the hopes that she would fall in love with him, not for who they were back then or who they are now, but for what they can aspire to be: happy, fulfilled and blissfully in love with one another.
33-year old Han Je In is a mystery novelist who is notorious for habitual false reporting to the police in town. Her only friend is police officer Rok Hwan, who has had a crush on her since childhood. One day, Je In hears a scream of help from an apartment upstairs and reports that a serial killer lives above her but no one believes her. Convinced that Jason, the handsome man living upstairs, is a serial killer, she asks Rok Hwan to help follow him around with her. But as she learns more about Jason in her pursuit to uncover the truth, she begins to fall for him. Seeing her in this state, Rok Hwan feels a tinge of jealousy.
Hanamura Aiko is a skilled lawyer who specializes in divorce cases. She is a warm-hearted person who sympathizes with clients who are suffering from marital problems, but she grew up seeing her parents' discord, and has lost faith in romance and love. She dotes on her recently adopted dog, Sakura, and is enjoying her single life. Shirosaki Kai is the director of a 24-hour animal hospital who deals with life every day. He is loved by staff and patients for his good looks and skills, but he doesn't talk much about himself and keeps people away from him. A year ago, he rescued a stray dog ??that was brought to the hospital and named it "Shogun". One day, while walking Shogun, Kai meets Aiko with Sakura. At that time, the two dogs fell in love at first sight, and the destinies of the two began to change. Woo So Ha is a friendly young man from Korea who is popular wherever he goes. Woo So Ha has come to Japan with a mission and tries to get closer to Kai, and by chance, he also meets Aiko.
A romantic film about a man struggling with a painful past as he tries to move forward, only to discover that the woman in his present life has an uncanny connection to his past. Together, they navigate the complexities of love, heartbreak, and healing, all against the backdrop of cultural and identity differences in the foreign city.
