As the Hong Kong government gradually eased its border restrictions, many mainland Chinese, who were stuck overseas during the Covid-19 pandemic, opted to enter and quarantine in Hong Kong as a transit point before returning to mainland China.

However, Xu is unexpectedly stranded in Hong Kong because the options for re-entry to the mainland are scarce, due to the large influx of visitors. One day, she goes to the China-Hong Kong border to visit her mother whom she has not seen for many years.