追放された錬金術師は無自覚に伝説となる ヤンデレ妹（王国の守護竜）と一緒に辺境で幸せに暮らします！

ウィンザー公爵の長男マイスはある日、国王から辺境への追放を命じられる。One day, Mys, the eldest son of the Duke of Windsor, is ordered to be exiled to the frontier by the king. He was secretly visiting the strongest dragon that protects the kingdom [Guardian Dragon Valitra], which is considered to be a rebellion against the kingdom. However, the true identity of the guardian dragon Valitra is actually Mys's younger sister Tiny, who was thought to have died four years ago! “Mys-nii-sama is my lifesaver, and he is the one who is worthy of ruling over everything in this world. He is the supreme and supreme being. Anyone who hurts Mys-nii-sama will be thrown into hell by me. !” The kingdom, which has incurred the wrath of the guardian dragon Valitora, will be on the road to destruction... Meanwhile, the frontier where Mys became the lord achieved unprecedented development through his alchemy, and everyone became happy.