ここは都内、湾岸地帯にある湊十区（みなとく） 気がつけば年の瀬も終わる大晦日。 成稜学園の何でも屋、黄昏部に所属する後代灯（ごだいともり）は、いつになく頬を引きつらせていた。 卒業まであと少し。みんなで楽しめる最後の年末年始だからと、部員たち4人と一緒に訪れた神社の二年参り。 夜店で騒ぎながら、スカートをめくってギリギリを見せつけてくるコトナに、おっぱいをその形がわかるくらいに当ててニヤニヤほくそ笑む奏。 結は恋人さながらに腕まで組んできていい匂いがするし、澄玲は気にもせず間接キスをする始末。 そんなHなカノジョたちのいる部……じゃなくて。 星泉コトナには、卒業までにやりたい事があった。 『ぜったいに、セイカ祭を過去イチ盛り上げてみせるんだから！』 かつて、カリスマ生徒会長として彼女が導いてきた成稜学園。 最後くらいは、その伝統ある一大イベントでなにか足跡を遺したい。 そんな想いのコトナを扶（たす）け、今まで学園行事に無関心だった黄昏部面々が、本気でセイカ祭に望む。 だが、そこへ再び現れた、不思議な黒いカードと不可解な謎のメッセージ。 それには未来の部員へ託された、黄昏部設立当時の真相が綴られていた。 すべてを知って愕然するコトナたちに、より強く頑なに自らの意思を固める奏。各々の願いと信念が交差する。 歯車が花びらを散らしながら回り始めた。そして遂には、日常を蝕む終わりの鐘の音が学園中に響き渡る―――。 果たして、お祭りの盛り上がりのゆくえは？ 黄昏部の真相とはいったい。 主人公・後代灯と星泉コトナのちょっと不思議で、楽しいエッチな物語が今幕を開ける。

Tokyo Bay Area, somewhere in the Minato Ward. Today is the last day of the second semester, the end of the year approaching. Godai Tomori, a member of the Twilight Club, the anything-goes club at Seiryou Academy, sighed even louder than usual. Kanade, the club president, skillfully works and simultaneously converse with him. While emphasizing her big boobs. Then, the former student council president Kotona interrupts them with a handful of sweets. And also shaking her big boobs. Meanwhile, his underclassmate Yui would tangle and tease him whenever she has the chances. Not to forget pushing against him with her obviously—again—big boobs. In this situation, the maid secretary, Sumire, made him a cup of tea with a smile. The glimpsing views of her deep cleavage is very soothing, and that indicates a presence of yet another pair of big boobs. The Twilight Club... is not actually that kind of booby club. Surrounded by pretty girls, Tomori is happily working away despite the hustle and bustle. It's an end-of-the-year tradition, an annual cleaning in gratitude for the year. As they are all noisily cleans up the club room, Tomori find an ''old box'' that he doesn't recognize. When he opens it, he find a small key and a letter from an unknown sender inside. "I am the Black Traveler." "The Celestial Sphere of Time has been destroyed, and the world's balance has been disturbed." ——is the nonsense that is written on the letter. This is the last mystery (Alicegram) left behind in the Twilight Club. What is the meaning of this letter? And how will this change his relationship with the girls? What kind of future will they choose? The mysterious and exciting erotic story of the protagonist, Godai Tomori, is about to begin. [Edited from [url=http://nanawind.jp/product/prj06/chapter1/]Official Website[/url]]