Secrets are those pesky little things that (a) keep Tris from feeling really close to her friends and family and (b) protect Tris from her enemies, who would kill her if they knew her secrets. (Secret #1: She's Divergent. Secret #2: She didn't love The Avengers.) Because she wants to keep her secrets, Tris ends up lying to several of her friends. But at the same time, almost all of the villains here have secrets that they use to manipulate and have power over others. Secrets give you power, sure, but they can also threaten that power, which is something Tris knows all too well.