You Can't Bluff the Sharp-Eyed Sister manga volume 1 features story by Natsu Hyuuga and art by Chiho Shinishi, the creator of The Apothecary Diaries.

In a sleepy countryside church, Chloe plays the part of a prim and naive novice, studying to become a cleric. But when night falls, she sneaks out in disguise to win big money at cards! Despite her best efforts, word gets around, and one day a handsome young holy knight named Erald - known as a rising star in the capital - arrives to enlist her help. A murder two years ago threatens the stability of the kingdom, and Erald thinks this card shark in sister's clothes can solve it using her charism - the rare blessing that allows someone to use magic. Little does Heraldo know, there's nothing supernatural about Chloe's winning streak. She's just got a quick wit, and sharp eyes! Will that be enough to survive the den of devils that is the great church?