Natsume discovers that the heirloom "Book of Friends" that his grandmother, Reiko, gave him possesses the names of the spirits she defeated and bound to her will. Assisted by a cat whom Natsume addresses as Nyanko-Sensei (lit. Master Little Meow), Natsume aims to return all of the names to their rightful owners.

Natsume is visited by the village's local god who is currently fading because of the lack of devotees.

Natsume is implored to help spirits who are currently being exorcised. He finds a kindred spirit in Tanuma, a boy who also senses spirits although not as powerful as Natsume.

Natsume's secret is found out by Sasada, the class president, during the "Trial of Courage." She asks for his help to find the spirit that lives in the abandoned school. Natsume denies the fact that he can see anything, but she won't take no for an answer. Meanwhile, the spirit, Shigure, captures the rest of their school mates, in fury of the school being torn down...

Natsume comes across an old ticket in Reiko's belongings and decides to go to the abandoned train station to see why she kept it. There, he meets a slow witted spirit named Santo, who was waiting for Reiko the entire time to go Kiriganuma, to see and make up with his friend, Mikuri, but the trip isn't as easy as it first seems...

Natsume is possessed by a swallow spirit, who wishes to meet a human who once helped her. Natsume agrees to help her and the two grow attached. When Swallow finds the human, Natsume feels bad that she can't actually meet him, but when he hears of a kimono that can turn a spirit into a human for a day, he looks for it.

Natsume goes to a hot spring for a school trip, with an errand from Shigeru to pick up teacups from a near by pottery. While there he meets and helps a little fox spirit, who quickly grows attached to him.

Natsume meets a spirit who used to be friends with a man who could also see spirits, but one day lost this ability.

Natsume meets a popular actor named Natori Shuuichi who can also see spirits, and has a side job as an exorcist.

Natsume is possessed by a sick koto player, whose friend wants her to be able to play one last time.

When Natsume finally has enough of Nyanko's behavior, Nyanko leaves, wandering about by himself and causing trouble.

Natsume is cursed by an evil spirit which is sealed to a tree. Not wanting to trouble his adoptive family, he decided to run away from home.

Tanuma finds out that Nyanko-Sensei is a spirit. Tanuma and Natsume enjoy the autumn festival and previous acquaintances are seen again.

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 is dragged off into the cave of the evil spirit that is after Taki. He temporarily loses the ability to see youkai after being poisoned by the spirit. Will he be able to stop the youkai from eating Taki without his sight?

(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)