We open with a bright, very hot sunny day. Rin is returning from a shopping trip, and is eating ice cream. While Rin is walking, the scene shifts to a security guard station where a small two tailed cat with horns is apparently waiting for someone. The security guards talk about the cat, which has apparently been hanging around for quite some time now; the cat is someone’s familiar, and unfortunately for all concerned, his human is dead.
After the opening credits, we discover that Rin had been sent to the store for water, not ice cream. This leads into an argument where Rin is complaining about not advancing far enough and Yukio pointing out that Rin isn’t applying himself to his studies. (He also points out that Rin can’t even go on a simple errand. Rin feels this comment was uncalled for.) Yukio also makes some valid comments about Rin relying on his powers and on his sword to get himself out of trouble, which Yukio doesn’t approve of. Then the argument devolves into name calling highlighted by Rin breaking Yukio’s glasses.
Their argument is interrupted by a phone call. Yukio has been called away on a mission and Rin wants to follow. Yukio however, does not feel that Rin is competent enough to go with. This does not stop Rin from following anyway. This sparks another argument, but eventually, Yukio relents.
It turns out that the cat from earlier has gone completely berserk. (It’s a “cat sidhe” according the subtitles.) Rin can hear the cat calling everyone liars as it throws a temper tantrum of truly epic proportions. We learn that this cat was the familiar of Rin and Yukio’s adoptive father, and it is upset about his death. (We also learn that this particular cat sidhe was befriended by Shiro after the cat’s shrine had been destroyed.)
While the exposition is occurring, the cat sidhe is attacking, and the exorcists are attempting to knock him out with tranquilizer darts that don’t work. The cat attacks and the exorcists go for their guns. Rin meanwhile, can hear the cat having hysterics over Shiro’s death. We get some more exposition where we learn that Yukio was on hand on the day that Shiro first tamed the cat sidhe. The cat had apparently been the god of a shrine and had the job of protecting silk farms from rodents. Over time, silk production ceased in the area where the cat sidhe had been living, which had caused people to abandon its shrine. Shiro and a group of exorcists had been called on the scene because the cat sidhe had gone berserk after it’s shrine had been destroyed (We also discover that Shiro had been the Paladin of the order at one time.)
Yukio believes that he is going to have to kill the cat sidhe because it is definitely out of control again. To do this, he has a potion that Shiro had given to him for the purpose. He believes that the potion is a poison that will kill the cat. Rin however is feeling a great deal of sympathy for the cat, and believes that Shiro would not want to have the cat euthanized.
Yukio is extremely reluctant to go along with this, but Rin decides to take action, promising to “use his head.”
Before Yukio can take action, Rin calls out to the cat, introducing himself to the cat and telling him that Shiro is dead. The cat is understandably upset by this and refuses to believe him. The cat attacks, but Rin “uses his head” with a head bonk that somehow manages to knock the feline tail over teakettle.
(The look on Yukio’s face is priceless.)
Rin then goes over to the cat, and they spend the next few minutes talking about Shiro. Rin is extremely sympathetic, and is able to somewhat calm the cat down. While Rin is talking to the cat, Yukio remembers that Shiro had used almost the same words to talk the cat down from its temper tantrum. (Of course, it probably also helped that Shiro also gave the cat “silver vine” sake. “Silver vine” is a plant that has similar properties to catnip.)
The cat shrinks down to normal size, and cries his little heart out.
The scene pulls back and reveals that Mephisto and Amaimon have been watching the entire incident. Mephisto asks what Amaimon thinks of Rin. Amaimon states that he isn’t able to make any sort of assessment concerning Rin at the moment. The reason is that Amaimon hasn’t really seen Rin fight yet. Mephisto asks Amaimon if he’d be willing to fight Rin. Amaimon indicates that he is willing to fight Rin, but first he wants to do a little sightseeing. Amaimon heads out and we see that the teacher from the last episode was also watching. Mephisto and the teacher engage in some cryptic conversation about Amaimon and Rin.
In the next scene we see Rin and the cat, who seems to like Rin a great deal. Yukio turns up with the good news that they will be able to keep the cat. Rin and Yukio discover that the “poison” Shiro had given Yukio had actually been silver vine sake. (Since the stuff had been kept in a modified holy water hand grenade, Yukio assumed it was poison.) We end on a happy note, though Rin discovers that “silver vine sake” is not something that humans or non-cat demons should ever try to drink.