Ririko, a stylish Charisma Gal from Shibuya, finds herself playing amateur detective after an unexpected turn of events. She is keen to solve cases to prove herself worthy of elite police detective Nii, a man she adores and regards as her fiancé, but her enthusiasm leads her into a whole lot of trouble.

Nana is twenty four years old and has lived most of her life without any purpose. She is known to her coworkers to be indifferent and refuses to pay attention to others when they speak to her, leaving her with very few friends. However, Nana’s life is turned upside-down when a car accident sends her back to her past; she awakens to find that she is now a fourteen-year-old junior high school student. As she relives her junior high school days, she slowly begins to uncover the painful memories that she had tried to repress as an adult. Will Nana’s past help her find a reason to live or will it prove to be much more than she can handle?