The Last Bell by Alex Lidell

Hostages. Memories. Heartbeats. The long awaited finale to the epic Power of Five story is here.
The quint has finally reunited, but their stunning new discovery changes everything.
Just as Lera and the males navigate their redefined future, Owalin violently ups the stakes, giving the humans one hour to hand over their kingdoms. Lera must do all she can to help defeat him, even if that means facing down her own males—and the humans themselves.
Because in the fight for the mortal world, every life—and every heart—will lie on the line before the last bell sounds.