Ritsu Onodera yearns to edit Japan's top-selling novels and believes Marukawa Publishing is the ideal place to achieve his dream. Unfortunately, his hopes are dashed when he is assigned to the Emerald department, responsible for producing shoujo manga, and under the supervision of his uncompromising boss, Masamune Takano. In a desperate move, Takano even kisses Onodera to provide reference material for an artist, leaving him demoralized. However, Onodera is determined to prove himself and secure a transfer to his preferred department, fuelled by the memories of his high school ex-boyfriend and first love.
Gradually, Onodera gets comfortable in Emerald's all-male team and the romantic themes of the manga remind him of his past, although he tries to avoid dwelling on his ex-boyfriend. Instead, he focuses solely on his work, learning from Takano even though the latter appears to have a strange fascination with Onodera's history. Eventually, they realize that they already know each other; Takano is the one who had broken Onodera's heart. However, Takano points out that it was Onodera who abruptly left him without any explanation.
With the editors at Emerald already knowledgeable about romance, they soon discover their one great love. For Onodera, it is merely a matter of time before he comes to terms with the fact that he is still very much in love with his first relationship – the "world's greatest love."
