A shy eighth grader buys a magic mug and gets a fairy that grants wishes, but the fairy can't actually help with love. Every wish backfires in ways that force her to face what she's actually afraid of. By the time she realizes the magic was never the point, the boy she's been running from has been watching the whole time.
Eighth grader Kaede stumbles into an antique shop and buys a peculiar cocoa mug on impulse. When she discovers instructions etched inside and follows them, a small blue fairy named Mirumo materializes in her home. According to the rules of the muglox realm, Mirumo is bound to grant her wishes, but there's a catch: he's the spoiled prince of the fairy world, far more interested in chocolate and causing chaos than actually helping anyone. Kaede wants nothing more than to confess her feelings to Yuuki, the boy she's had a crush on forever, but Mirumo's constant interference and mischief make every attempt hilariously complicated. As they're forced to work together, an unlikely friendship forms between the anxious girl and the impish fairy. Mirumo slowly discovers there's more to life than getting his way, while Kaede finds courage she didn't know she had. The show balances magical romance comedy with genuine moments of growth, blending slapstick humor with real stakes as both characters learn what it means to care about someone else. It's equal parts wish-fulfillment fantasy and coming-of-age story.