Twenty-eight-year-old corporate slave Lin Chen, in order to save someone, accidentally reaches a pact with a deity. His consciousness travels back in time to his youth, possessing the young girl Lin Chenchen. Possessing adult memories, she must live as a girl alongside her younger self, Lin Chen. Amidst living together day and night, lingering memories continually emerge. While shaking off the constraints of past consciousness and searching for her true self, Lin Chenchen accompanies and understands the clueless young Lin Chen. Crossing the confusion of memories and inner struggles, the two realize their true feelings, moving from noisy bickering to a mutual sprint towards each other, joining hands to start a brand-new life belonging to them.