Story
Under the table is the angel's secret. The boy's name was Hitori. A stork brought the angel into the lives of a middle-aged couple who were not blessed with children. His parents were kind, his house spacious, and his meals hot. But to protect the happiness he had received, Hitori continued to hide an important secret from his parents... (Source: Anime News Network) Note: Includes three extra chapters.
Synopsis via AniList (English).
Preview
From the anime adaptation: Migi&Dali.