After a fierce marital argument, Yusaku was left in despair as his wife moved out. Seeing Yusaku like this, his wife's sister, Serino, offered to mediate. With her beauty and caring nature, Yusaku felt reassured having Serino's help. He rejoiced at gaining a reliable ally. However, Serino was biding her time, waiting for Yusaku to let his guard down. Eventually, when Yusaku seemed completely smitten, she suggested he take a bath and began undressing herself...
