(from ebookjapan):

In late 14th century Spain, there was a swordsman from Navarra called Falco (falcon). He repented from his days of fighting and became a monk, but...?　

From his encounter with Don Pedro, King of Castile, to his friendship with the unique friends of the Lilienthal Monastery, to Falco's exploits in difficult cases, you will be amazed!　

Also included is Portrait of a Laughing Cat a work set in a medieval monastery.