Xiu Xiu, a 15-year-old girl living in the city of Chengdu, moves out to study horses in the countryside with a nomadic Tibetan. She is told that after six months, she will return to take charge of her all-girl cavalry unit. However, she quickly discovers that she is not returning. She learns lessons about life while struggling against corrupt government officials who manipulate her hopes and body. Her only friend is the eunuch horseman, Lao Jin.
Ami, a backpacker from Japan who is four years older than high school student Jimmy, shows up at his part-time job. The two end up spending the summer working at the same store, but Jimmy gradually develops a faint crush on Ami. The two of them grew closer as they rode motorcycles together at night and went to the movies, but suddenly, Ami decided to return to Japan. Ami proposes her "one promise" to Jimmy, who can't sort out his feelings. As time passes, Jimmy visits his parents' house for the first time in a while and finds a postcard that Ami sent him 18 years ago when she returned to Japan. Jimmy's memories of his first love come back to him, and he takes his first solo trip to Japan to confront his past and examine his present. Jimmy rides the train while listening to songs that remind him of his memories with Ami, and he heads to her hometown. Will Jimmy be able to reunite with Ami?
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.
Emilia, a Filipino who arrived in Japan with aspirations of becoming a model, coincidentally encounters Matsuyama Mirai, an aspiring photographer. Their connection deepens as they find themselves drawn to each other. Mirai, intent on immortalising their moments together, diligently captures their essence through the lens of his camera. However, an unexpected parting disrupts the flow of their narrative. Subsequently, the saga of these two individuals unfolds beyond the shores of Japan, traversing the vast sea to the Philippines, where their story takes on new dimensions.
L, an angel who’s endlessly fascinated with the human world, gets into trouble when she unthinkingly saves the life of Han Shi Yeong, a man who was meant to die. To make up for her mistake she must guard him on Earth for one hundred days and keep him safe from Hwan, a death god who is required to collect his soul. Both supernatural beings must contend with the knowledge that whichever one of them fails by the end of the hundred days will be erased from existence, and the longer they stay on Earth the further their powers fade and the more human they become.
Mika goes all the way to Seoul to see her sweetheart Hyeong Jun who's been waiting for her. She suffers faints at the airport and she mistakes Kim Gyeon as Hyeong Jun due to trauma. Kim Gyeon also ends up falling in love with her, thus disrupting the balance between the three. Their memories start intertwining, but, before long, a tragedy occurs.
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.