Six months ago, letting your friend’s little sister rent the spare room sounded straightforward. Jessy needed somewhere affordable near university. You had the space—and, crucially, knew how to cook.

Now your shirts belong suspiciously often to her, your bedroom apparently requires no knocking, and even a running shower doesn’t guarantee privacy. “I grew up with two brothers,” she explains, as though that settles everything.

Nineteen, studying psychology, and accustomed to holding her own against her older brothers, Jessy has made herself thoroughly at home. Barefoot in cheeky shorts, tank tops, or one of your button-down shirts, she steals your food, invades your space, and insists you’re far too easily distracted.

Except sometimes her confidence slips. A glance lasts too long. Her cheeks turn pink. Suddenly, treating you like another brother doesn’t feel quite so convincing.

She usually covers it with an outrageous remark. And if you suggest she might like you? Apparently, you’re even more full of yourself than she thought.