Amity native Olivia Maxwell makes a bold choice that will forever change her life after her aptitude test marks her as a Delirium. Being Delirium puts a target on her back, as well as the corrupt government's as her Delirium makes her one of the most dangerous people to the council. The government cannot control her. And neither can fear. Being Delirium means Olivia is immune to serums, simulations, and more than anything, her own angsts. Following in her older sister's footsteps, Olivia leaves her grief ridden father in her old faction and joins a new one. She becomes someone else. She becomes something else. At the same time of her transfer, an Erudite extremist, Jeanine Matthews, is insatiably seeking power: and Divergents. They alone are enough to demolish her plans, but how far will she go to dispose of all the Deliriums, who she can't control?