Tearmoon Empire Novel Volume 15 was written by Nozomu Mochitsuki and illustrated by Gilse.

Between a horsemanship tournament to save Ruby and a cooking party to prevent Sapphias from staging a coup, Mia's been busy this summer! It's not quite time for her to kick up her heels yet, though. Patty is despondent and desperate to see her brother after coming face-to-face with Gerta, so Mia plans a trip to the former Clausius domain. It looks like it'll be a family trip since Emperor Matthias wants to come along too!But when Patty finally learns the truth, what will become of her? Will she be freed from the Serpents, or will she fall further into their clutches...?