The premise sounds like a punchline, but the show commits to the awkwardness with actual comedic timing. Keita's resistance crumbles in real time as he stops pretending he doesn't want what his sisters are offering, and that slow surrender is funnier than any setup could be. The fanservice isn't window dressing here, it's the entire point, and the show knows it well enough to make you laugh instead of squirm.
Keita's life takes a chaotic turn when his step-sisters, Ako and Riko, suddenly confess their romantic feelings for him. Since they share no blood relation, the twins see nothing wrong with pursuing their affection, but Keita remains uncomfortable with the situation. He's determined to keep things strictly sibling, even as he prepares to enter the same high school where they study. The closer Keita gets to his sisters at school, the harder it becomes to maintain his resolve. Between their relentless advances, awkward encounters with classmates, and the everyday chaos of teenage life, Keita finds himself caught between genuine family bonds and something far more complicated. His attempts to establish boundaries constantly crumble under their persistence and charm. This comedy balances genuine character moments with outrageous humor as Keita navigates the impossible situation he's landed in. The show moves at a rapid pace, jumping between comedic misunderstandings, embarrassing public moments, and surprisingly tender interactions. It's a lighthearted take on forbidden romance that doesn't take itself seriously, offering fun for viewers who enjoy romantic comedy with an eccentric twist.