The Death Cure Book by James Dashner

The Death Cure is the third and final book in the Maze Runner series, where the protagonist, Thomas, must lead his friends through a final, dangerous test from WICKED to find the cure for the Flare virus. Having recovered more of his memories than WICKED anticipates, Thomas knows the organization cannot be trusted and sets out on a quest to save his friends, facing terrifying truths and a dangerous final confrontation. The book follows Thomas, his friends, and other characters as they escape WICKED, deal with the infected "Cranks," and navigate the treacherous landscape of a post-apocalyptic world in a race to the truth.