Taking the mantle of Kamen Rider Zi-O, Hikaro Cabral must gather together heroes from different worlds and dimensions in an effort to stop the Fallen from reviving in 100,000 days. But is it enough? When the Alliance comes across a strange artifact from the past, they find out that if they are to truly defeat their enemies once and for all and save the Multi-Verse too. However, they will need all the help they can get. But not from their Universe, the entire Multi-Verse itself!