Mamori reveals to Itsuki that the producer of her show, "Microwavin' with Mamorin", has decided to change the direction of the show by adding a skit involving Mamorin making a meal for her sister. However, because Mamori is an only child, she doesn't know how to act when it comes to siblings. As such, Itsuki suggests they practice at Uzume Lesson Studio, inviting Eleonora to help.
Eleonora agrees to help, revealing that she has three younger brothers and thus has experience with siblings. With guidance from Itsuki, Mamori is able understand what being a sibling is like, causing her Performa to awaken. After performing Radiant Unity, Draug admits that he's glad Mamori is able to act her age, as she is always trying to help her friends. The next episode of the show includes the skit, which ironically features Eleonora as the older sister. Afterwards, Mamori notes that Itsuki is like an older brother.
Completing this side story unlocks Mamori's Special Performance Microwavin' Soul.