Amatatsu is a brash, but normal high school student until he wakes up in the middle of doing it with another guy!! To make matters worse, the culprit is his biggest rival, Sen! Is it really possible he's come to a parallel world where he and Sen are a couple...!? In addition to the main story, there are other complicated love stories about a guy with a voice fetish, a boy with a crush on his best friend, and a chubby chaser. Also has previously unpublished material. 気は強いが平凡な男子高生・葛西に訪れた悲劇。目覚めると男とセックスの真っ最中だったのだ!!　しかも相手は犬猿の仲である同級生の依岡で!?　どうやらパラレルワールドに飛んでしまったらしく、その世界で二人は恋人同士だという。大嫌いなライバルとエロい関係だなんて…!?