"I want you to become my familiar and protect me." ".....What?" One day, a middle-aged man who claimed to be the Demon King suddenly appeared in front of Rian, a high school girl. The old man even asked her to become his "familiar"! Despite being the Demon King, the old man is surprisingly serious and kind!? And so, her life under contract with Uncle Demon King begins....「使い魔になって、私を守ってほしい」「…………は？」。女子高校生【りあん】の前に、ある日突然、異世界の【魔王様】が現れた。 しかも、りあんに【使い魔】になって、自分を守ってほしいとお願いしてきて――!? 意外とマジメでやさしい(?)魔王おじさんとの契約生活はじまります。 魔王と女子高校生がまさかの運命共同体!? イケオジ魔王様×女子高校生使い魔、契約ラブコメディ！