Episode Summary: Kuroha is busy cleaning when there is someone at the door, and when she opens it she is in for a surprise. Back with the rest of Astral, their hiding place was found out and they festival began. The rock where the ghost’s hatred was held is crushed by a magical black hand, which seizes Kaori. It turns into a giant demon, and Honami sends Tatsumi on a giant stock to retrieve Kaori. The giant demon simply breaks the stock to peices and disappears. They regroup and realize the plan, and Tatsumi and Itsuki agree that they have to get them back. Meanwhile, Mikan is being lead up the the top of the highest mountain; as the group races them to the top, Tatsumi tells them about the last festival and the death of their mother.
The demon shows up at the festival site with Kaori inside it and is restrained. They tear off the demon’s horns which also hurts Kaori. The demon enters the sacrificial room, and Kaori and Mikan talk; Mikan states that she finally has a purpose, but Kaori will not take that. The demon expels Kaori and focuses its attention on the clan outside performing the ritual. The demon goes berserk and consumes all of its creations; when Nekoyashiki, Honami, and Tatsumi arrive, it is too late, the demon is going to destroy everything. Mikan and Kaori escape, but Kaori is taken away. Mikan stops everyone and states that she will participate to the very end, and the rest of Astral along with Kaori agree to help.
Mikan and Kaori use the absolute purification to keep the demon stationary while Itsuki and Honami take the offense. Itsuki rips off his eyepatch and commands Honami to fire her mistletoe in order to completely immobilize it. Mikan and Kaori finish the purification, but the demon is just too strong. Just before the demon crushes Itsuki, Adilisia appears to save the day. Mikan and Kaori start up the ritual again and defeat the demon. The grandmother states that she wanted the demon to take Mikan because of her low magical abilities, and Itsuki states that only Mikan can decide what she does with her life. They take their leave ending Rental Magica Episode 20 “The Festival of the Oni”.