[About]
Beside a mysterious door stands a girl who has accidentally wandered through it—Dorothy. She seeks your help to defeat the monsters lurking behind the door.

[Eligibility]
Reach Union Level 22.

[Event Rules]
1. In this challenge, you can choose "Dorothy's Companions" as Echoes to assist you in battle, which greatly enhances the combat abilities of Resonators.
2. Downed Resonators will be automatically revived after a while.
3. You can complete the task with your Friends.
4. You can only use designated Echoes in this mode (Sonatas will remain effective and only the main Echo Skill will be replaced).
5. Point Calculation: Clearance Points + (Remaining Time x Time Coefficient).
The Total Points will be the sum of the highest points achieved in regular levels. (Points will not be awarded for challenge levels).