Xiao He, a poor peasant girl in ancient times, had a mother suffering from consumption who was bedridden year-round, and her father worked away from home making it hard to care for the family. She was forced to put off marriage, relying on digging wild vegetables in the mountains and supporting a seven-year-old younger brother through difficult days. When a heavy rainstorm forced them to hide in a cave, the siblings accidentally triggered a two-way spacetime channel, and the heroine time-traveled to the modern marketplace. Accidentally discovering that ancient eco-friendly wild vegetables were highly sought after in modern times, she traveled back and forth between the two worlds ever since. On one hand, she sold mountain goods and wild vegetables in modern times to exchange for money and medicine to support her family; on the other hand, she purchased food and medicine from modern times to bring back to ancient times. Relying on cross-spacetime commerce, she step by step cured her mother and led the whole family out of poverty.