In Nanjing in 1937, Ye Lansu, a female physics student, accidentally triggered a wormhole in the laboratory and awakened Gu Yunshen, a military scientist from 2045. In the midst of the war, he, who knew the scars of history but was unable to change them, and her, who was tenacious and persistent, supported each other, and their love gradually grew.
The knowledge about the future brought by Gu Yunshen has become both a sweetness and a curse - every small intervention to protect each other triggers a violent backlash of time and space, and the historical faults continue to expand.
Knowing that separation is fate, the two still stick to their love in desperate situations and make a promise to "see each other again at the end of time." In the end, Gu Yunshen stepped back into the wormhole to repair time and space, leaving only Ye Lansu and a blank diary, waiting for the promise that spanned time and space over the years.
