Frieren's party finds a grimoire containing the magic that every man dreams of... penis enlargement magic. Knowing that Stark is extremely conscious about his size, Frieren casts the spell onto him... only for him to lose his mind and go on a sexual frenzy. This leaves Fern with no choice but to accept all of Stark's raging sexual desires, rendering her incapable of doing anything else but moan and cum relentlessly.
At first, she's hesitant about having to have sex with Stark, but gradually, she succumbs to the pleasure and easily shows off her erotic face as if she's fallen in love. Even if the magic stabilizes, it is uncertain if Fern will ever stop having sex with Stark...