If You Let Us Stay Over… We'll Let You Do Something Naughty♡ Mitsuhiko Okaya, a down-on-his-luck man, is betrayed by both his wife and his junior at work. Mocked as a useless "window-sill editor" at his company and sinking into despair, he suddenly encounters two high school girls he should have never met—yet somehow feels a strange sense of familiarity. There’s Akari, the lively, cheerful younger twin who loves to playfully tease him, and Nanako, the shy, awkward older sister who hides a surprisingly naughty side. It turns out… they were once his students from the cram school where he worked during his college days.