The Divergent Series is a film franchise based on a young adult novel series by author Veronica Roth. The confusion between my son, who has read Allegiant but not seen the film, and myself, who has seen the film but not read the book, revealed that a few small changes have been made in adapting the third and final Divergent novel to screen.
Fans will tell you it's not the first time the plot of The Divergent Series has been messed with. And there's a sense the biggest shocks may be yet to come as Allegiant follows the trend of splitting final books into two parts, with Ascendant scheduled for release in 2017.
It's a shame really, as Allegiant's conclusion, without the more-to-come cues, would have made a perfectly satisfying ending.
In Allegiant, Tris (Woodley), Four (James) and her group of renegade divergents Peter (Miles Teller), Christina (Zoe Kravitz) and Caleb (Ansel Elgort) finally make it over the wall that separates post-apocalyptic Chicago from the rest of the world.
They're quickly welcomed into another walled city that is also a mix of industrial grunge and futuristic modernism, and home to the creepily named Bureau of Genetic Welfare where they learn the slightly underwhelming truth about their existence in Chicago as part of a grand experiment.
There are plenty of surprises, about Tris' family and her genetic makeup, and the unveiling of the world outside Chicago in the Mad Max-like Fringe, but for all this Allegiant heads in exactly the direction you expect and far too slowly.
A lack of tension and a cyclical plot does little to draw you into this lacklustre third outing, and leaves you wondering if you even care about the fate of Tris and her mates.
The Divergent Series has been losing momentum since the first film - at least they've got one more chance to get it right.
Shailene Woodley, Theo James, Jeff Daniels
M (Violence) Verdict: Amazingly, it's not over yet.
Amazingly, it's not over yet.