After Siren tricks Hibiki into getting another fight with Kanade, the two discover they have been entered into a 'Best Friends' tournament. Wanting them to make up, Hummy suggests that they each spend a day in each other's shoes. As such, Hibiki spends some time with Kanade's family whilst Kanade's stays over at Hibiki's house, where she starts to understand some of Hibiki's loneliness when her busy parents aren't around. With the two making up with each other by the next morning, Siren attempts to spoil their friendship on the day of the contest by posing as Hibiki's mother, Maria, saying she shouldn't stay with Kanade. However, this is foiled when the real Maria shows up in the audience, having come from her overseas work to give Hibiki support as per Kanade's suggestion. Siren makes a Barometer Negatone which is too powerful for their normal attacks. Realising they shouldn't rely on Muse to save them, Hibiki and Kanade combine their Belltiers to form the more powerful Belltier Cross Rods which manage to defeat the Negatone.
響は、朝から奏の様子がおかしいことに気づいていた。そこでハミィの提案で、仲直りするためお互いの家に交換ステイすることになった。だが、奏は毎日店の手伝いをしたり、奏太に勉強を教えたり大変で...。
