Gurin the gnome loves to play tricks on others. In spite of several warnings he just can't help himself, and one morning he wakes up with a foxtail as punishment. Rumors of his fabulous tail soon reach the capital, and the widow Stengelføhn-Glad tries to hire private detective Solan Gundersen to find Gurin. She wants to be the envy of her upper-class friends by owning the luxurious foxtail. But Solan and his sidekick Ludvig doesn't want to see Gurin come to harm. And after refusing the assignment they set out to find the gnome before the widow does.