I Don't Need a Trashy Sub-Male Lead

Layla lost her beloved mother. When her new stepmother and stepsister arrive, she regains memories of her past life. She realizes this is the world of a novel she was obsessed with, where she is fated to die at age 21. However, she is poisoned instead of dying from illness. Just before dying, she is sent back one year in the past. She decides to take revenge on those who ruined her.

Original Webtoon:
KakaoPage, Bomtoon, MrBlue

Official Translations:
Japanese (Localized):
Horizontal, Vertical