Maggie, a top planner of the March 3rd Grand Festival, falls into a river during her mother’s push for marriage and time-travels into the infamous "useless" wife of Prince Charlie. Framed for arson by a fake heiress, she is trapped in a deadly situation. Using her modern intelligence, she fights back, exposing schemes and seizing control of the Ancient Valentine’s Day preparations, blending traditional culture with modern ideas like bronze drums, string instruments, and so on. As she grows closer to Charlie, she survives repeated plots by Maria, but is eventually stabbed. Maggie returns to the modern world and reunites with Charlie, completing their cross-time love story.