In 1999, a robbery-murder case occurs in a small supermarket in Samnye, Jeonbuk province. The police investigation quickly narrows down to three boys from the neighborhood, and these boys are falsely accused of being murderers overnight and are imprisoned without understanding what is happening. The following year, veteran detective Hwang Joon-cheol is newly appointed as the head of Crime Investigation Division. He receives a tip about the real culprits and embarks on a reinvestigation to clear the boys' names. However, the interference of the detective responsible for the case at the time, Choi Woo-sung, leads to everything falling apart, and Hwang is demoted. Sixteen years later, the sole witness of the case and daughter of the victim, Yoon Mi-sook, and the boys return to Hwang, seeking justice...

'Lee Seon' dreamed of becoming a wise mother and wife, leaving her unfortunate past behind. But there was no proper man in this world! Thinking that starting over was the only way out, she dreams of a new love by faking suicide. Absurdly, 'Lee Seon' faced a real death! The moment your breath stops, the seven-day time slip door opens to look back on past relationships... Will her love be rewarded?