On his first night as a lost and found subway officer, Cheng Wu picked up a talking red umbrella.
Red Umbrella refused to register and only reported a murder that had not yet occurred:
"00:17, Old Port Station. Your new supervisor will kill my master."
A minute later, the new supervisor Zhou Du swiped his card and entered.
There is no Jiugang Station in Linqi City. At least that's what the maps, surveillance and all living memories say.
Cheng Wu still followed the red umbrella and found it.
Then she saw with her own eyes that a wrong return caused an entire street to disappear from the city.
Later, she learned that every lost object that wakes up is waiting for a choice: the object, the memory, and the path traveled. Only two of the three can be left.
Zhou Du is responsible for deciding for the entire city who should be forgotten.
Plot: A subway lost and found agent searches for lost items for non-humans every night, until a talking red umbrella reports that its owner will be killed by her new supervisor at 00:17.