Insurgent is the sequel to Divergent, both of which I enjoyed. I think that both films are better than what you might expect considering that they both have weak reviews. The second film starts slow and is a little predictable, but I feel that the last act redeems it.
Both movies take place in a post apocalyptic future where what is left of humanity lives in a walled off Chicago. Their society operates on a kind of caste system, where each person must choose at a young age which caste to live in. The five castes are Abnegation (the selfless), Amity (the peaceful), Candor (the honest), Dauntless (the brave), and Erudite (the intellectual). Beatrice Prior, or "Tris", is born into Abnegation, but chooses to live in Dauntless. In Dauntless she is severely tested but slowly rises to the challenge.
Tris carries a secret, which is that she is "divergent", which means that she can fit into more than one caste. The government doesn't like this and apparently considers divergents to be uncontrollable and dangerous. Ultimately, Tris must fight against corrupt forces in the government.
Divergent: * * *.5
Insurgent: * * *