The Reason My Boyfriend Married My Older Sister

Everything was going well in both her love life and her career. That was until that day came. Miyata Aiko (Akita Shiori), who works at an apparel store, lost both her parents at a young age, but lived a happy life with her kind older sister Saeko (Takada Riho) and her childhood friend and boyfriend Yoshimura Yuma (Kageyama Takuya), a doctor. Then, just before her 25th birthday, Aiko is told by Yuma, "I have something important to tell you," and her heart starts beating fast, thinking, "Maybe he's going to propose to me?" However, one day, on her way home, someone pushes her from behind, causing her to fall down the stairs and fall unconscious! When she wakes up, she learns an unbelievable truth...