While local ruffians frequently came knocking to press for debt repayment and Su Yinian was at her wits' end, a pair of little brother and sister from the Prince Chu's Mansion appeared out of thin air inside her own supermarket. A mysterious iron door connects the modern supermarket with the Great Zhou Chu territory plagued by disasters. Su Yinian initiates cross-space-time trade, outputting food and disaster-resistant potato high-yield seeds in exchange for the Prince's Mansion's antiques, gold, and silver to pay off high-interest loans. Chu Yu acquires life-saving supplies to comfort displaced commoners and also has to resolve family conflicts of the Dowager consort believing in a fake fairy nun; Su Yinian faces harassment from dark and evil forces directly in the modern era. The two guard the transaction agreement across time and space, looking out for and helping each other, seeking a glimmer of survival for two worlds.