You Can't Bluff the Sharp-Eyed Sister

Chloe, who works as an apprentice priestess in a remote church, is a money-loving girl who makes a lot of money at night by gambling at cards, using her insight and memory as weapons. When Erald, a rich holy knight, visits her, he asks her to infiltrate the church as a candidate for sainthood and find the murderer who committed a murder two years ago...?

Alt. Official English: K Manga