A journey through the realm of the dead. A threat that will change the world. A choice that might save everything-or end it all.
As natural disasters sweep Earthside, a mutant army rises in the Borderlands, driven by the dark force behind the Shadow Cartographers.
Sienna and the Mapwalker team must use the Map of the Impossible to journey through the realm of the dead and face the nightmare at its heart.
But when one of their number is taken and the team begins to break apart, each Mapwalker must face their greatest challenge.
Can the Mapwalker team reach the Tower of the Winds before the Shadow claims Earthside? Will Sienna choose Finn - or turn away from the Borderlands forever?
