The group is back together again working on saving the various worlds from a crisis. It's harder to do when not everyone has their powers back yet but they don't give up.
Amulet Books sent me a copy of the book to read for review (thank you). It has been published and you can get a copy now.
They have old enemies to watch for and a brand new one called the Time Trapper. He wants to end the world.
There's time travel, fantastic battles, and sacrifice required by all of them. It's not going well for them. They can't destroy the Time Trapper.
As time goes on they try lots of different things.
This is the last book in this series. Will they manage to save the world or will it all just disappear?