ティガからギンガとビクトリーまでの10大ウルトラマンが一堂に会するのは本作品が初であり。
突如現れた謎の時空城から現れた女戦士アレーナで、惑星ザントの出身。ウルトラマンを『邪悪な者』『平和を乱す敵』と認識し、「魔鏡」と呼ばれるアイテムを使ってウルトラ戦士を次々と封印していく。戦いを挑むギンガとビクトリー、そしてUPGの仲間達であったが、戦いの最中、別宇宙よりやってきた青年・春野ムサシとウルトラマンゼロまでもが現れる。

This is the first time that the top 10 Ultramen from Tiga to Ginga and Victory have all gathered together in one place.
A female warrior named Arina, who appears from a mysterious space-time castle that suddenly appears, is originally from the planet Zant. She recognizes Ultraman as an "evil person" and an "enemy that disturbs peace," and seals the Ultra Warriors one by one using an item called a "Magic Mirror." Ginga, Victory, and their comrades from UPG challenge them to a battle, but in the middle of the battle, a young man from another universe, Haruno Musashi, and Ultraman Zero also appear.