A young man who aspires to become a big-shot businessman, finds himself in a twist of fate. Despite trying his hand at various jobs, success eludes him, and he unexpectedly ends up in Osaka's Shinimamiya district. With empty pockets, he stumbles upon an invitation to the 'Gokuraku Toruko' establishment, becoming a patron. Led by the enchanting Ibohachi, he becomes entangled with the charismatic hostesses, including the captivating Tama. This leads him to infiltrate Tama's apartment complex, Sakura-so. Within its walls reside a colorful cast of characters, from hostesses Chie, Akemi, Yukari, and Kayoko to the quirky parasites like Masao, Tetsuo, Arima, and more. Seeking a fresh start, He embarks on a journey as a 'parasite,' but things take unexpected turns...