When Haru’s parents told him he’d be staying overnight at his cousin Mio’s house, he groaned. Mio was younger, loud, and always broke his toys.

"Shinseki no ko to o tomari da kara" in Japanese could mean something like: "Because it's staying with a relative's child…" (though the grammar is slightly off — possibly 親戚の子とお泊まりだから — "because I'm staying overnight with a relative's child"). If you’re looking for a based on that idea, here’s a short one: Title: The Unexpected Sleepover

But that night, a storm knocked out the power. Mio didn’t cry. Instead, she grabbed a flashlight and said, “Let’s tell monster stories!”