The opening of this episode is a replay of the last few minutes of the previous episode. Rin and Izumo are attacked by a demon. The demon, which looks like some kind of bird, knocks Rin around, but Yukio arrives in time to drive it off, and then we go to opening credits.
The next scene is the rest of the class discovering Rin and Izumo cleaning up the mess left behind by the bird demon. We discover that classes have been canceled so that everyone can go find the demon and check all the barriers to find out how the thing got in. The class is assigned to checking the barriers, but Rin is held back so he can continue his training exercise.
In the next scene, we learn that Konekomaru has been missing since at least this morning. Shima is wondering if this is a sign that Konekomaru may be thinking of leaving the cram-school, but Ryuji doesn’t want to believe that this could be possible. He states that Konekomaru made a promise to become an exorcist, and doesn’t believe it’s possible that Konekomaru would quit.
Konekomaru meanwhile, is being tempted by the demon, which has partially taken over his body. It promises to help him kill Rin and spends a great deal of time trying to get Konekomaru to cooperate. It preys on Konekomaru’s fear of Rin and fear of being abandoned by his friends. After some struggle, the demon manages to get Konekomaru to go along with its plans.
When we get back to Rin, we see he is not closer to completing the exercise correctly. He’s bored and frustrated and would rather be out hunting demons. Yukio is not impressed, and tells Rin to start taking his training seriously. He starts into a lecture, but stops suddenly, and appears to be in pain. Rin asks what’s wrong, but Yukio brushes him off, and leaves the room, telling Rin to continue practicing. (We will later see that Yukio has some kind of marking on his shoulder.)
Rin agrees, and then decides that he’s going to go off on his own to hunt the demon. He’s interrupted in his escape attempt by Konekomaru. Rin sees the demon hovering over Konekomaru’s shoulder and immediately attacks, which leads to some misunderstandings. (His classmates panic and assume that Rin is attacking Konekomaru for no reason, since they can’t see the demon.) Rin of course is not able to explain himself very well, and meanwhile, the demon is laughing at him.
Next up is Shura and one of the teachers. They’ve found a van that turns out to have some kind of portal in it. Shura and the teacher investigate and discover a forest on the other side of the portal. Further explorations reveals some kind of abandoned and burned out laboratory facility.
We return to Konekomaru and Ryuji. Ryuji questions Konekomaru on where he’d been all of this time. Konekomaru doesn’t really answer the question however, stating that he doesn’t remember. Ryuji tells him to rest, and the conversation wanders onto the subject of Rin. Konekomaru asks Ryuji what he thinks of Rin. Ryuji states that he does not consider Rin to be very reliable, and in general considers him to be an idiot. He’s also outraged that Rin asked Ryuji to believe in him. (Ryuji feels that if you’re going to say something like that, there should be something to believe in, and in Rin’s case, there kind of isn’t.)
Konekomaru admits that he finds Rin to be terrifying, but Ryuji feels that there is nothing particularly scary about Rin, except maybe his power. He further states that there is “just nothing there.” (Presumably, nothing there inside Rin’s head.) After some more conversation with Konekomaru, Ryuji gets up to leave, and it’s revealed that Ryuji’s shirt was singed by Rin’s flames. Ryuji is not in any way bothered by this, (and it seems as if only the shirt was damaged by the flames) but Konekomaru is extremely alarmed. The demon turns up and makes another pitch for Konekomaru’s full cooperation. This time, it’s successful.
The demon manifests and dives out the window with Konekomaru. Ryuji races downstairs where he meets up with Shima, who had bought a comic book for Konekomaru. Ryuji tells Shima to go get Yukio because Konekomaru had been possessed, then takes off after the demon.
The next scene is Rin up on the roof brooding about his earlier encounter with Ryuji. As he’s lying there the demon turns up and attacks him. The scene shifts to Yukio who finds that Rin is not in their room. Yukio gets a phone call and is alerted to what happened to Konekomaru, and then he sees Rin and the demon falling past the window.
Next we’re outside and Rin is losing the battle with the demon, who has become fused with Konekomaru. Yukio attempts to take the demon down, but he is not successful. Ryuji tries to get Konekomaru to snap out of it, but this is also not effective. What is effective is Rin, who manages to talk Konekomaru down. (He tells Konekomaru that he should be relying on his friends, not on the power provided by the demon currently possessing him.) The demon’s hold on Konekomaru falters, which causes the demon to begin to retreat, taking Konekomaru with him. Rin yells for Konekomaru to jump free of the demon, then leaps into the air to catch him (simultaneously destroying the demon with his sword).
The next scene is Shura and Yukio reporting what happened to Mephisto. (On the desk is a hamster who looks a great deal like Amaimon.) Then the conversation shifts slightly to Shura’s discover of the burnt out research lab. It seems that this particular lab had been doing experiments on artificial life. Mephisto states that this should be investigated immediately
Meanwhile, Konekomaru has decided to leave the school. He has lost all confidence in himself and his abilities, so he is running away. Rin is not happy about this and provides Konekomaru with a pep talk. Konekomaru cannot compute why Rin is insisting that they’re still friends, even though Konekomaru tried to kill him. Konekomaru recalls Ryuji’s earlier statement that there was nothing going on in Rin’s head, and states this out loud. Rin immediately tries to prove that there is something inside his head beside the sound of the wind whistling, but is not actually successful. We end the episode on a happy note, with Ryuji and the rest of the class having caught up with Konekomaru. (Rin is immediately upset because the rest of the gang “stole” his pep talk spot light. They rag on him about it and make him carry Konekomaru’s bags.)