Kaede, a vivacious eighth grader, gets very anxious around boys. However, her life takes a drastic turn after discovering an enigmatic store and acquiring a magical cocoa mug. Upon opening it, a message discloses a fairy who will grant her wishes if she reads the message aloud and pours hot cocoa in the mug. Desperate to win the affections of her crush, Yuuki, Kaede follows the instructions but summons a mischievous blue Mirumo instead of the love fairy. Unbeknownst to Kaede, Mirumo is the royalty of Muglox and has fled his kingdom to avoid marriage to his fiancée. He is hunted by the bounty hunter Yashichi and several Mugloxs, all with distinct personalities. Kaede and her friends get dragged into an unexpected adventure with these captivating troublemakers, turning their school lives into an entertaining journey.