Two Japanese boys go on a real-life Manga adventure when they discover what a single night in Shinjuku holds for unwary lovers.It's the night of Gacchan's birthday and boyfriend Takayuki is waiting at home to celebrate. But Gacchan has not only forgotten about his party, he's been out playing around. Furious, Takayuki leaves, threatening not to return until he has indulged in some adultery of his own.