While my sister is away on her trip, I, Kiyotaka, the only son, have been tasked with house-sitting at her luxurious apartment. Though a bit exasperated by my sister's disregard for Yuuko and our plans, I can't hide my joy at getting to live in such a grand mansion. Seeing me like this, Yuuko smiles. 'Mom, let's take a bath!' I suggest to Yuuko, eyeing the bathtub that must be three times the size of ours at home. And so, the two of us end up spending some 'mother-son alone time' in the bath…
