From the time Yan Shuhan first started remembering things at age five, certain images kept flashing through her mind.
During another mission, she encountered someone whose face matched that of a person in those visions. She deserted her organization, was gravely wounded, and was rescued by that woman, becoming her younger sister.
A few years later, her sister was found by the organization while away on a business trip. Yan Shuhan stormed the organization's headquarters alone and rescued her.
But when she was injured, she ended up in another time and space.
There, she met one person after another from her visions, and her memories began to return.