It has been since childhood that Mega has lived with his uncle. This happened after his parents got divorced, his father went out of nowhere, and his mom chose to live by herself. This unresolved matter makes Mega hate his mom because she abandoned him during her toughest time. A year after his mom passed away, one day, his uncle gives him a home certificate owned by his mom to be bequeathed to him. At the beginning, Mega refuses it; however, his uncle forces him because this is a right for Mega. His uncle asks Mega to come back home and live there to take care of it. Mega obeys his uncle’s demand due to a moral duty. Mega goes to that home and starts living there. He cleans up everything and plans to sell that home. While cleaning it, he accidentally finds a diary with an interesting leather cover; it is written “don’t open it!”. Mega starts reading it, and then how surprised he is when he knows that the book is owned by Nana—his mother's foster child. Little by little, his past becomes clearly explained. He knows the truth about his mom.