Season 3

Natsume is approached by someone he knew from elementary school. He wants nothing to do with them, but they threaten to reveal his secret: that he can see Youkai, if he doesn't come along with them. He reluctantly goes with them, and is taken to meet a strange girl...

Midterms are over, and Natsume leaves on a trip with Nishimura, Kitamoto, and Sasada. He realizes that the scenery he's viewing from the train is from one of the places he grew up in, when he was passed around from one family to the next. He'd thought he didn't have any good memories of the time, but then he remembers what happened when he lived there...

Natsume helps clean the stoeroom at Taki's house with Tanuma. He realizes that one of the kimonos that her grandfather, who researched youkai, used to ward off demons was missing, but decides not to tell them so they won't be scared. But that kimono was an old doll youkai, who was trying to recover its body which was torn apart when her grandfather sealed it

There is something killing Youkai and draining them of their blood. Natsume can't help but investigate and runs into old friends.

Natsume finds out who's been stealing the youkai blood: the exorcist Matoba Seiji. He investigates with the help of Natori, but is captured by Matoba's servant youkai. Matoba is willing to sacrifice any number of youkai for his own ambitions. He tells Natsume why he's gathering blood: to release the seal on a powerful youkai. Natsume learns that there are people who treat Youkai in a totally different way than he or even Natori.

Natsume is invited to go to a pottery classroom with Shigeru. It's being held in an inn where he once stayed. When he goes there, he meets an old friend: the young fox child he once saved.

Without Sensei to protect him, Natsume has to remain constantly on guard. But the pressure of keeping secrets from his friends is causing Natsume to break.

After a brief incident in the forest, Tanuma has become distant to Natsume like he is avoiding something. In the meantime, there is something breaking glass around the school.

Tanuma is experiencing how Natsume lives every day. While Natsume and the youkai gain an understanding.

A youkai from Natsume past has found him and memories of living with relatives before the Fujiwaras are explored.

The youkai hold a party to celebrate Natsume. Things get out of hand when they ask Natsume for a human game, and he suggests Shadow Tag. When Nyanko-sensei becomes "it", he starts stomping youkai left and right. And then Misuzu-sama, the 100 foot tall youkai, shows up...