Chisato lives with her daughter and her husband. - She lived in harmony with her family of three. - Chisato, who had been awake in the middle of the night, noticed a sound leaking from her daughters bedroom. - When she peeks secretly, her daughter and her husband are working. - She returned to her room, thinking that she was on good terms with her. - However, Chisato was aching her body for the work that was done every night...