I Gave My Lying Sister a Truth Serum

【Started a Long Story】 Serena, the daughter of the noble Valstein family, is unilaterally told by her fiancé Kyle that their engagement is broken off due to a lie told by her younger sister Lydia. Lydia, with tears in her eyes, repeatedly appeals that "my older sister did terrible things to me," garnering sympathy and attention. However, Serena, from years of experience, immediately sees through that her younger sister is lying again. Having no choice but to accept the broken engagement, Serena begins preparing for counterattack together with her best friend Annette. The method she chose is a "truth serum." Using it, her plan is to make Lydia speak the truth with her own mouth at a social tea party.