Sequel to Itsuka koi ni naru made. Uke and seme have been together now for 8 years, previously childhood best friends who ended up together. Their other best friend shows up pregnant and leaves her baby with them, then leaves for a job overseas. They end up taking the baby girl and raising her as their own. Mom keeps in touch with phone calls but they basically all act like baby girl is the uke and seme's child now. She grows from baby to toddler in this story
Kazoku Ni Narouyo