After barely surviving the attack on the Makanuele Rumble, Balt and Alani set out with their friends on a dangerous journey across the island to find a laboratory that might hold the key to learning what truly happened to Balt's grandparents eight years ago. The Summoners will have to battle mutant Jekuas warped and strengthened by their toxic environment, search for a way to repair the mana leak that threatens to plunge Alani into perpetual soulsickness, and avoid the attention of their enemies. Surviving the island won't be enough because the supposedly abandoned lab is still in use—and a threat deadlier than any they've faced before is waiting.