According to the "Hong Kong Poverty Report 2020" released by the government at the end of 2021, the population of the poor in Hong Kong will reach 165.3 in 2020 (before policy intervention) and the poverty rate will reach 23.6%, which is a record high and the problem of disparity between the rich and the poor in Hong Kong is becoming increasingly serious.

The story's protagonist, Hei, is given a chance to talk to his mother because of a metal box he has never seen before, a white Petunia flower, and a stack of photos of him and his mother, which allows him to magically learn about the day his mother died.