2025年の暮れ、東京での生活に慣れ、季節の情緒を失いかけていた「僕」のもとに●校時代の恋人のみつりから5年ぶりの連絡が届く。別れに明確な理由はなく、ただ遠距離という時間が二人を疎遠にさせていた。しかし今の恋人に後ろめたさを感じるほど僕の心には「初恋」という名の消えない（おり）が沈殿している。再会の場所に指定されたのは横浜。かつての自分たちには遠すぎたその場所で止まっていた歯車が再び回り出す。期待と不安が入り混じるなか僕は「もう以前の自分には戻れない」という予感を抱えながら約束の当日を迎える__。ドキドキした…5年ぶりに再会した「みつり」はあの頃と変わらないあどけない笑顔を見せつつも大人になって美しくなっていた。マンネリ…セックスレス…欲求不満…互いにパートナーがいるがお互い上手くいってはいなかった。当時は飲めなかった酒を飲んでたくさん笑った。やがて2人の理性は揺らぐ…あの頃の記憶を取り戻すように…朝まで互いを何度も求め合った。セックスの相性が抜群だった2人の1泊2日W不倫デート

At the end of 2025, having grown accustomed to life in Tokyo and almost losing touch with the changing seasons, "I" receive a message from Mitsuri, my high school sweetheart, after five years. There was no clear reason for our breakup; the long distance had simply caused us to drift apart. However, a lingering feeling of "first love" remains in my heart, making me feel guilty towards my current girlfriend. The place chosen for our reunion is Yokohama. The gears that had stopped turning in that place, so far away from our former selves, begin to turn again. With a mix of anticipation and anxiety, I face the day of our meeting, carrying the premonition that "I can never go back to being the person I used to be." My heart races… Mitsuri, whom I've reunited with after five years, still has the same innocent smile as before, but she has grown into a beautiful adult. Monotony… sexless… frustration… we both have partners, but neither of our relationships are going well. We drink alcohol, something we couldn't do back then, and laugh a lot. Soon, our rationality wavers… as if trying to recapture the memories of that time… we desire each other again and again until morning. A two-day, one-night affair between two people with amazing sexual chemistry.