I Transmigrated to the 1980s, but I'm No Pushover

Zhu Yu, a modern female soldier from a military family, works herself to death and suddenly returns to the 1980s, where she becomes a mentally disabled girl with the same name.

Her original sister never gives up on her, doing everything in her power to protect her, but is cruelly killed by villains.

Inheriting this body, Zhu Yu gradually turns to the dark side and vows to avenge her sister.