Natsume takes care of an abandoned egg from a nest, not considering it could be a Youkai. After it hatches it turns out it is a rare baby spirit called Tatsumi, who thinks that Natsume is it's parent. Natsume can't help but get attached to the little spirit even as Tatsumi grows tired and sick. But as Natsume takes care of Tatsumi a mysterious spirit comes, and wants to take away Tatsumi for his master... who wants to eat him!