The series 'Oyasumi Sex' follows a collection of interconnected stories that delve into the intimate and emotional experiences of various characters during different late-night hours. From 2:00 am to 4:30 am, viewers witness a range of encounters, reflections, and personal revelations that shape the characters' relationships and self-discovery. As the narratives unfold in each installment, themes of vulnerability, desire, and connection are explored, culminating in 'Oyasumi Sex: Soushuuhen' that provides a comprehensive compilation of these poignant tales. The spin-off 'Natsuyasumi Sex' further expands on the themes of intimacy and growth, offering a new perspective on the complexities of human relationships.