In the late autumn of 1948, Chen Jiaying is working undercover for the underground Communist Party. Betrayed by a comrade and shot dead on the top floor of the Peace Hotel, she is reborn on the day she checked in there in 1947. The pocket watch she activates contains a storage space that can hold objects but not living things, and at first it can only slow the spoilage of food. Using her foreknowledge, she saves Lin Mo, a progressive student who was supposed to die, and discovers that he is actually an underground Party liaison. When the two exchange intelligence in the hidden pockets of a qipao, a change occurs in the space: invisible writing appears on any paper they touch.
