The Erudite faction has risen up and taken over. Through the use of simulation serum, they've managed to override the individual thoughts of people's brains in Dauntless and turned them into lethal fighting machines; that is all but the divergent.
The divergent can't controlled by the Erudite leader Jeanine Matthews, and until now, were able to hide their identity from the rest of the world. For some reason, it is not only dangerous to the higher ranking members of society to be divergent, it is a right to the city as the anomaly has roots that lead back to secrets of their inception.
Hinging on the morning Tris wakes up to her closest friends marching in robotic lines and she's still aware, she realizes what's going on. A civil war of sorts has begun in her former faction of the Abnegation and it's with this bloody battle that secrets are revealed not only in her family, but in her friends. There are more divergent members of society than Tris knew, and now it's obvious who they all are.
Tris and Four work to reverse the effects of the Erudite's leaders attempts to control society. They meet both successes and failures along their journey, and together they cross important trust bridges in each other. Seeking safety in the Amity compound, Tris seeks to unlock the secrets that are tearing apart the life she knows.
This books reveals a lot of the characters back stories to help the reader understand their current roles. For example, Beatrice's mother was from Dauntless and was divergent - who knew? A secret well-kept Tris's entire life. Tobias aka Four was an abused child which explains some of his reserved and very complicated character traits. Families are exposed, people are torn apart, and wickedness abounds as members of the society choose to pay their loyalties to Jeanine Matthews or Evelyn, Tobias suddenly not dead mother that lives among the Factionless.
Insurgent is a book of choices, of defining roles, of acts of valor.
But - I do have one complaint here, and I'm paraphrasing from a wonderful blog called "The Book Smugglers": I am not a fan of these protracted angsty love stories. It’s comedic, because of the chastity; it’s frustrating, because SO MUCH TIME is spent on these exact. same. exchanges. repeated ad nauseam – meanwhile, there’s a WAR going on, people! Needless to say, characterization in this novel and the focus of so much of the book on Tris and Tobias’s romance kind of bummed me out.
But overall, I would still say this novel was a good read. It moves with a brisk pace and in the end, a highly improbable, but not so insane it's completely unbelievable, plot twist sparks the reader's imagination propelling one into the final book in the series: Allegiant.