Episode 15 at first shows an old-man demon whose main power seems to be ingesting a lot of alcohol and breathing green smoke that makes other people see pink pigs that turn into dangerous snakes. Lúci is sitting in the bar where the demon is wreaking havoc.
Meanwhile, the Angels are standing around at rehearsal reflecting on what happened when Crow came in. Reiko gets a phone call from Kirari's manager, who is standing beside a truck with the Hearts' picture on it. Next thing we see, the Angels and Reiko are in their van heading over there. They see a poster that advertises Kirari and the Hearts and having a joint concert. As soon as they walk into the concert hall, a book hits Reiko in the face. Although I've wanted to do that since the series started, the credit actually goes to Kazuya, who follows it up by saying something the Angels don't like. Hishou goes after him, but Kazuya simply steps aside and Kyle leaps forward to protect him.
Incidentally, the Hearts are already wearing their long black coats and stage make-up. Hishou goes for Kazuya again and this time Kirari gets in the way. Hishou throws a temper tantrum over Kazuya in the backstage area while the other Angels talk (Ginga is putting on make-up with a powder puff).
The Angels are next seen dressed up as the Hearts (wigs, make-up, clothes) while Kazuya inspects them (not surprisingly, Hishou is the one dressed as Kazuya). The Angels rehearse at the instruments posing as the Hearts. When the actual concert begins, the Angels (still in costume) are watching the Hearts perform on a backstage monitor. The old-man drunk demon shows up.
Kazuya is interviewed with Kirari and talks about his background. We see him as a kid who didn't have anything in common with other children until he started playing a guitar and then they all flocked to him. Kazuya seems to issue a personal challenge/insult to Hishou (maybe something about his not belonging on their stage). The Hearts perform again, the Angels are watching from the wings in costume. At a certain point, the Angels run onstage and take the place of the Hearts.
The demon arrives and unleashes his power on the audience. Hishou is about to act when Kazuya puts a hand on his shoulder and speaks to Kirari. He starts playing an acoustic guitar while she sings a different song than usual. No one else is making a sound onstage but the two of them. The song seems to nullify the effect of the demon. The Angels are watching and even Hishou admits it's pretty cool. The demon mutates in a big white flash into a worse-looking demon, and Kazuya quickly gets Kirari off the stage as the audience is attacked.
There's an onscreen five-way transformation for the Angels. Eagle Flare and Condor Lance are used, but the snakes coming off the demon grab Falcon, and then Crow shows up, cutting the snake in two with Crow Sword. Crow says something to Hishou that reminds him of something Kazuya said, and so realizes who he is. Crow uses an attack Crow Cut, coming off as two shots that hit either side of the demon. He then tells the other Reideens something about what's going on (concerning the gems and the bad guys etc) and they seem rather shocked by it.
When his back is turned, the snakes attack Crow and then the other five Reideens. They're hopelessly trapped until a rainbow attack hits the demon--Reideen Isis has arrived. His outfit is green and gold, with an elaborate Egyptian design on the chest and cool backswept 'feathers' on his helmet. Crow knows him. Isis uses the attack Isis 'Subyuto' that uses a pair of drumsticks which attach themselves to the demon with long ropes (looks like a whip). He uses Isis Rainbow again. It goes down the demons throat and the thing explodes from the inside out. Crow and Isis go off together while Lúci watches.
Later, Hishou, his mother, and Tsubasa watch Kazuya and Kirari being interviewed again, Kazuya says something about believing in power. Hishou looks very intense as he watches.
Meanwhile, the other boys aren't too happy either. Hishou stands onstage alone, listening to Kazuya's voice in his head. His feather appears on his arm. He makes what sounds like a vow concerning Crow/Kazuya.