Ban Xia, the greatest assassin of ancient times, retires only to be hunted down. She unexpectedly travels a thousand years into the future, arriving in Rongcheng. Struggling to adapt to modern society, she fails to earn money performing on the street because she has no payment QR code. Gu Yuanming, the man she rescues, takes her in as a shop assistant, offering her food and lodging. He seems unsurprised by her unusual behavior, yet his eyes conceal a profound longing. While diligently providing therapeutic treatments at a wellness shop, Ban Xia guards against her enemies' schemes and plots her revenge back in ancient times. She helps everyone at the shop, turning it into a warm haven. But harassment from competitors and assassins pursuing her across time shatter the temporary peace, while Gu Yuanming's mysterious tenderness hides secrets of its own.