The Ring of the Seven Worlds #1

Seven planets linked to one another by the multidimensional gates of a giant ring. Only the passage to Nemo, one of the Seven Worlds, has remained sealed for three centuries in order to imprison its people after they savagely attacked the rest of the Empire. When the infamous gate reopens and unleashes the ancient enemy, Timo and Luce, two teenagers from the planet Mose, are caught up in a war they were not prepared to fight.