The final summer vacation of our third year. It was more restrictive and shorter than I expected... days spent being chased by summer courses and homework. In the midst of that, we decided to have a two-day, one-night overnight study session while our parents were away! The members were supposed to be me, Tomonori, Mika, and Natsu—four of us! But... by a prank of fate, the only participants ended up being me and Natsu. Natsu and I can't exactly be called just friends... more than friends, less than lovers... it's a bit ambiguous, and we both know we're conscious of each other... there was a special kind of heat between us... Studying side-by-side... "Just the two of us. You don't hate it?" "If I hated it, I would have gone home." The conversation cut off unnaturally... in the silent room, our gazes overlapped as if drawn together... with Natsu letting her true feelings slip, the distance between us closed instantly! ...An unauthorized kiss, and I could feel our body temperatures rising all at once... instead of words, we sought each other out intensely! Forgetting all about studying, we had passionate sex! We leaped over the boundary of being "friends" that existed until yesterday... a clumsy confession of "I love you" exchanged while watching sparklers. Eating cup noodles together. The two of us sought each other out repeatedly until morning... and then, in the kitchen illuminated by the morning light, we carved our existence into each other greedily! Even though we did it so much yesterday... I want to do it even more! Seeking each other out youthfully and intensely! The summer vacation that was supposed to be cramped transforms into a free paradise for just the two of us! A bittersweet, youthful, erotic love story!