Professor Layton's daughter, Katrielle Layton, runs the Layton Detective Agency together with the talking dog Sherl and her assistant Ernest, and solves strange cases that happen everyday in London. Originally, she started the job with the purpose of finding her father, Hershel Layton, who had disappeared suddenly, but her incredible ability to solve puzzles made her well-known and she receives numerous requests.

The first short story focuses on Favaro and Kaiser between the events of the first and second series as they visit Favaro's home village. The second short story shows Kaiser as a knight commander sparring with Jeanne, and sharing the reasons they remained as Orleans Knights in the aftermath of the final battle against Bahamut.

An unaired episode of Shinmai Maou no Testament, bundled with the eighth light novel volume.

Yotsuya and Ichinose are enjoying a hot afternoon when they recall the time that the tenants of Ikkoku-kan and Mitaka go off on a cruise to party hard aboard Mitaka's new boat; however, the boat falls apart, and everyone is shipwrecked on a deserted island. With everyone up to their usual antics and shenanigans, what can happen in such a desolate place?