My next door neighbor, Matsuri-chan, has always been cold and distant, so I don't really like her... But our parents get along well, and she's decided to look after me for a week while my parents go on a trip! Contrary to her brusque attitude, she's always messing with me whenever she gets the chance! She gets drunk and acts all slutty, and forces me to sleep with her...! And then I suddenly realize. My sister is actually into me...? A completely subjective experience of living together with the busty tsundere Matsuri-chan!