Keeper of Mine is based off of the novel and promotional webtoon, I'll Protect the Second Male Lead's Love! During the events of the book, you control and play as Leah Stephilia De Lenokyn as she navigates the world of 'From Hostage to Empress', a novel read shortly before her transmigration. Eager to save the tragic fate of the second male lead, Ain, she pushes the female lead towards him in hopes they can trigger their happy ending. Will she be able to save the second male lead's love?