The Arms Dealer Training Academy is dedicated to training the best of the best in fashioning special weapons from defeated beasts. But before prospective craftsmen can become fully-fledged Monster Arms Dealers of their own, they must first undertake a three-year apprenticeship. One exceptional student is given this task, but the master she meets proves much harder to cooperate with than she anticipated. What secret is her new master hiding, and why does he only create Monster Arms for specific client?