In Fuse, the fifth and final chapter of The Call of the Rift, Kateiko Rin faces her greatest challenge yet - herself. Reeling from the Fourth Elken War, Katja throws herself into a gruelling medical apprenticeship. Her fragile peace shatters when a rift tears open the world. In stumbles another version of herself: K, bloody and bruised, hunting the rogue wind spirit Suriel to reclaim her soul. Their plans go awry when they realise the rift is killing their worlds. Wildfires and drought devastate the coastal rainforest. Sky-rivers and rusty creeks defy logic. The girls' only hope of saving their homeland is waking ancient, powerful nature spirits - the exact thing Katja fought a war to prevent. The Kateikos forge a grudging alliance, but after nine years of their worlds diverging, they're each other's worst enemy. K is everything Katja's scared to be - cold, callous, and conniving. Katja has everything K lost - a home, family, and the affection of Tiernan, the fire mage they both loved. Friends take sides. Enemies take notice. Danger creeps closer - people Katja thought she escaped, people K killed in her world, people with grudges old and new. The Kateikos must find a way to calm the storm, because if their friction lights a fuse, nothing will survive the apocalypse.