Shukujo no Kagami Yamemashita. Toki wo Gyakkou shita Koushaku Reijou wa, Wagamama na Imouto ni Furimawasarenai you Seikaku Waruku Ikinobimasu!

"Die for me, dearest sister."

Betrayed and killed by her cunning half-sister Muriel, noble lady Christina meets an untimely and bitter end—or so she thought. When she suddenly wakes up three years in the past, she finds herself with a second chance at life and vengeance. This time, she refuses to be the ideal noblewoman everyone expects. Teaming up with her fiancé, the sharp-witted Second Prince Iril, who is investigating strange incidents along the border, Christina prepares to fight back. She's done playing the perfect lady—this time, she'll survive with a wicked smile.