[SPOILERS: If you haven't read the books, or seen any of the movies, stop reading. Now. Still here? Okay, but you've been warned.]

The "Divergent" series returns with "Allegiant," its third and second-to-last installment, starring Shailene Woodley as messianic "The One" protagonist Tris. Directed by Robert Schwentke, the film co-stars Theo James as Tris' love interest, Four, and it also covers half of the 526-page book.

Since it has been a full year since "Insurgent," we've compiled a primer of five things to get you ready for the new film.

1. It Covers the First Half of the Last Book
'The Divergent Series: Allegiant'"Allegiant" may be the title of the last book in Veronica Roth's best-selling "Divergent" series, but the adaptation's filmmakers have named the next and final movie in the dystopian tale "Ascendant" instead of the typical "Allegiant: Part II."

That clever decision may have confused movie-only fans into thinking the movies were based on a four-book franchise rather than a trilogy. But this is, like the penultimate "Hunger Games" before it, is just one half of the final book. The last film – to be directed by franchise newcomer Lee Toland Krieger -- is set for a June 2017 release.

2. There's a New Antagonist
"Insurgent" ends with Factionless leader Evelyn (Naomi Watts) executing Erudite leader Jeanine (Kate Winslet), so naturally this next installment features a new villainous threat to Tris and Tobias' future. Enter Jeff Daniels as the smarmy David, the head of the mysterious Bureau of Genetic Welfare – the organization beyond the "wall" that sealed off the population stuck in the Chicago Faction system as a decades-long genetics experiment. The Big Brother-like Bureau watches the Chicago community, "Truman Show"-style, without intervening (so far).

3. Eugenics Outside, Civil War Inside
Gone are the fear simulations (the most sci-fi aspect of the first two films) and the personality-based compounds. Now that they're on the outside of the world of factions, Team Tris is thrust into a new-to-them society full of such tech as: floating globes, hovercrafts, tall glossy towers, and bio-weapons – not to mention the Bureau's obsession with genetic "purity." Meanwhile, back inside the wall, Evelyn's Factionless crew fights with Johanna's united "Allegiant" (Octavia Spencer) for control.

4. The Love Story Is Tested
We haven't yet seen the movie, but given the attractive actors playing Bureau employees Matthew (Bill Skarsgaard) and Nita (Nadia Hilker), their characters are to resemble their counterparts in the book, each teaming with Tris and Four respectively -- forcing the couple to wonder if they're on the still on the same page.

Don't worry, though, there's no actual cheating in the book, so we don't expect any in the movie either (who would cheat on Theo James, even if it is with Alexander Skarsgaard's hot little brother?).

5. It "Diverges" From the Book
Although we won't spoil exactly where in the book's plotline "Allegiant" breaks for "Ascendant," one thing everyone wonders is whether the screenwriters' creative liberties extend to certain controversial twists in Roth's source material. There is still going to be a body count that includes some beloved characters, but even author Roth has commented that the end may not exactly mirror the one she wrote.

And according to some fans, the central prospect of those changes is a good thing (spoiler alert: that Tris won't have to sacrifice herself and die to save her friends).