My next door neighbor Hitomi has always been unsociable and cold, so I don't really like her... But our parents get along well, so she's decided to look after me for a week while my parents go on a trip! Contrary to her brusque attitude, she's proactive and gets involved with me! She watches my adult videos without my permission, barges into the bath in her school swimsuit...! And then I suddenly realize. My sister is actually into me...? A completely subjective experience of living together with the tsundere busty Hitomi!