Yuji Matsuura is a 30-year-old shut-in, mentally scarred from his old abusive workplace and too burned-out to look for anything new. Now, he's living with his dad, his new stepmom, and his new stepsister, Kanon. Kanon is cute, free-spirited, and cheeky—and she has no sense of personal space. One day, Kanon takes her teasing a little too far, awakening something unexpected for both of them. But their new relationship might be just what Yuji needs to help him turn his life around.