In the third year of drought, four-year-old Xiaosui awakens her longevity lock with a drop of blood, allowing her to travel back and forth between the famine-stricken world and another world. A handful of wild vegetables can be exchanged for ten yuan, a bag of rice and a few steamed buns can save her family from starvation. As the lock grows warmer day by day, the things she brings back become increasingly plentiful, from a single bag of rice to six months' worth of provisions, from her family's rice jar to the water supply of the entire village. Those who share the secret grow from just Grandma to the whole family, and eventually the entire village. She only cares about one thing: filling the rice jar and making sure her whole family has enough to eat.