It's been seven years since Yuuichi Aizawa returned to the city he once lived in as a child. Though many things happened to Yuuichi in his past, he can only remember bits and pieces. His parents left Yuuichi in the care of Akiko once again, and this time, he will attend the same school as his cousin Nayuki. Many different girls appear before him, and some of them seem to know him from his past. Yuuichi must now recover his memories of the dark secrets that he erased from his heart, before he loses his precious ones.
After losing their parents, twins Haruka and Sora travel to the countryside to start a new life. The two soon meet new friends in the shrine maiden Akira, wealthy Kazuha and well-endowed Nao, amongst others. As the days go by, Haruka learns more and more about the new ladies in his life, all the while being a patient confidante and good friend, leading him into their hearts, as well as their loins. Meanwhile, Sora can't help but have a recurring memory of her brother kissing her as a child…
Both have several elements in common, like heroine arcs and protagonists in towns from their past, featuring school life as well. Although the ecchi is far less pronounced in Kanon, both animes have a touch of surreality, and their similarities become immediately obvious when romance scenes come into play. While Kanon is the more enjoyable of the two (at least, imho), the genres featured in Yosuga no Sora would probably appeal to Kanon's fans as well.