A lengthy behind the scenes look at Insurgent explains the mystery box first seen in the trailer and where we find Tris and Four at the beginning of the film.

Amongst lots of behind the scenes footage are several highlights: A great fight between Peter and Tris, as well as our first look at Naomi Watts in the role of factionless leader Evelyn (the mother of Four).

We’re also promised no more world building – a frequent complaint about the first film, Divergent.

“The great thing about this movie is that we’ve gone through the setup of this world,” says Four actor Theo James. Adds Ansel Elgort, who plays Tris’ brother Caleb, “We already have all of the characters introduced. Now we can just tell a great story.”

The movie begins with Tris being chased amongst factions and “never let[s] up,” according to producer Lucy Fisher. Like the book, the film’s story begins in Amity where Tris and Four are taking refuge. We see the unveiling of Tris’ new haircut and several simulation sequences including the one found in the teaser trailer. Douglas Wick, the film’s second producer, confirms that Tris and Four will be brought to the factionless compound – but it’s not clear if they get there by jumping into a train coincidentally full of factionless like in the book.

As for that mystery box seen in the second trailer which left lots of fans stumped? “The box takes a lot of my favorite scenes from the book and puts them in the same place at the same time,” author Veronica Roth explains.

“In the first movie you don’t really know exactly what Erudite is up to. In Insurgent, it’s crystal clear,” adds Kate Winslet who plays Jeanine.

These comments fit with a theory one of Hypable’s readers presented when the mystery box appeared in the trailer. The reader believes that the Edith Prior video, found by Tris and Four at the end of the Insurgent book, is in the box, and Jeanine needs someone with three faction aptitudes, like Tris, to open it. For the film, Tris is probably the only character capable of opening it.

Insurgent opens in theaters this March.