At a certain junior high, a certain boy and girl meet. They reciprocated each other's feelings, became a couple, and filtered with each other. Eventually getting out of sync over something trivial, the two gradually found themselves becoming more irritated than thrilled—alas breaking up upon graduation. They thought that they had both turned over a new leaf with clear and refreshed mindsets, only to reunite in an entirely unexpected way. They thought they had turned over a new leaf with a clear and refreshed mindset—only to reunite in an entirely unexpected way. “I'm obviously the older brother here.” “I'm obviously the older sister, aren't I?” “I've always hated that selfish of yours, you dahm maniac” “I've always hated that self-centeredness of yours, you dahm otaku.” The new sibling each of their newly remarried parents had brought home… turned out to be the ex they had just broken up with. Out of consideration for their freshly remarried parents, the two put on an act of being close step-siblings. Yet, whenever they found themselves alone, their true relationship inevitably resurfaced.