Natsume is attacked by a youkai while retrieving a ball at school. In his haste to run away, he ends up breaking a youkai's seal, just like how he met Nyanko-sensei. Later that night, Natsume discovers a black lookalike of Nyanko-sensei, only to have him steal the Book Of Friends! As Natsume and Nyanko-sensei search for the black cat, they stumble across a gathering of youkai. The youkai plan to attack the humans for sealing their lord - the black cat Natsume's looking for. With Nyanko-sensei's help, Natsume gives back the lord's name and catches a glimpse of his fond and bittersweet memories of living among humans.

(Source: Wikipedia)

While fooling around in the snow, Natsume and Nyanko-sensei run into Gen, a forest guardian who lives inside a statue. Gen tries to take over Natsume's body, but instead takes over a snow rabbit that Natsume had made. Gen pleads with Natsume to help him find an evil spirit who destroyed Sui, his guardian partner, and Natsume agrees. But it seems Gen isn't telling everything he knows.

(Source: Wikipedia)

Natori invites Natsume on a hot spring trip. But noises from the closet and a kimono-clad figure dangled from the ceiling make Natsume uneasy. Not wanting to trouble Natori because of his kind gesture to enjoy the hot spring with him, Natsume investigates the hot spring himself. During the night, Natsume meets with the Youkai, where she comments that he is too soft, and attacks.

(Source: Wikipedia)

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 its 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.

(Source: Wikipedia)

Natsume encounters a spirit who was enslaved by his grandmother Reiko 50 years ago by writing his name on a torn page from the Book of Friends, and tying it to a tree in a forest. Can Natsume help locate the torn page? What was Reiko's intention of tying it to a tree?

(Source: Wikipedia)

There is a new girl in school, Taki Tooru. With her appearance at the school, circles resembling crop circles begin to appear. As Natsume tries to find out more about the circles and Taki, he is visited by another Youkai. Only this time, the Youkai isn't looking for his name, but for a snack.

(Source: Wikipedia)

Natsume, Kitamoto and Nishimura take a trip to an old inn to spend some time doing their homework. Surrounding the inn there is a lake in which is believed to live a mermaid.

(Source: Wikipedia)

From the day where a picture of a row of cherry trees in a desolate winter was obtained, every time Natsume wakes up, his room is covered in petals. Trying to solve the root of this activity, Natsume and Nyanko Sensei try to return the picture to Miya, a shadow figure who accompanies the picture. But why can't they return it to Miya?

(Source: Wikipedia)

Strange things start happening at Natsume's home, like Toukou's plants get destroyed, and a strange Youkai starts wandering around his house. Natsume then learns more about Reiko and her life in this town. He also learns how to get rid of the Youkai who's wandering around the house.

(Source: Wikipedia)

While out with Touko-san, Natsume spots a hurt youkai. Quickly he chases after it but as he goes to help it, it is eaten by a much bigger youkai. Natori and Hiiragi appear right after the youkai escapes and they invite Natsume to the Assembly of Conjurers. Here Natsume can not distinguish between human and youkai and is hopeful of finding people who understand him. Though this may be what Natsume has always wanted; he is too soft-heartened to realize everyone's intent.

(Source: Wikipedia)

Natsume encounters a young boy named Kai sealed in a coffin in an abandoned house. Natsume sets Kai free and finds out that Kai is being stalked by a youkai. After a time, Natsume becomes the target of this youkai and stops the youkai's stalking with Nyanko-sensei's help. In the end Natori who turns out to be the stalker and who sealed Kai in the coffin, tells Natsume that Kai is a Youkai.

(Source: Wikipedia)

Natori tells Natsume of a well near the mansion that holds a group of Oni. They are calling out to any Youkai. He also learns that Kai came down from the mountains to free the Oni. While looking for Kai, Natsume sets off one of Natori's traps in the mansion. Kai saves Natsume and heads off to kill Natori. Natsume follows him,to save Natori from getting killed. After he encounters him, he is forced to make an important decision: Which ones are more important to him? Humans or Youkai?

(Source: Wikipedia)