Dangerous Beast

The Secret of the Elderly Couple

Our Vow

First Friend

Heaven & Hell

Calm & Fury

My Briefs are Striped

The Wrong Morning

Illusory Sibling

Our Room

Uneven Hair

A Suspicious Stroll

Our School

A Terrifying Punishment

First Love

An Unlucky Invitation

The Ichijou Way of Discipline

The Woman Who Knows Too Much

Migi's Triumphant Solo

I'm Hitori

Lie Detector

Who Killed Mother Bird

Hot Apple Pie

The Boy Going Against God

Migi, The Lost Detective

First Baiser

Christmas Ghost

Hatching

Half-Bodied

Death's Throne

There's Nothing Harder than a Loaf of Bread

Dusty Woman

The Volatile Cherry Pie!

Beavers

Rose Fortress

Operation Stork

The Upside-Down Woman

The Bird Within Another

Our Revenge

Migi & Dali

Our Hearts are One

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 3 extra chapters.