It's been more than a decade since James Cameron's Avatar made its way to the silver screen. The visual effects spectacle, which tells the story of greedy humans trying to steal the natural resources of a distant planet, became the highest-grossing movie of all time, raking in $2.9 billion globally. 

Now its long-awaited sequel, Avatar: The Way of Water, is hitting theaters. The Way of Water is the first of four sequels. It'll continue the story of Jake Sully (Sam Worthington), Neytiri (Zoe Saldaña) and the ruthless humans who would pillage their planet, Pandora. They're not the only familiar faces returning. Sigourney Weaver, Giovanni Ribisi and Stephen Lang are listed in the cast, along with newcomers Kate Winslet, Edie Falco and Jemaine Clement, to name a few. 

CNET's Richard Trenholm says the film is breathtaking and clunky at the same time. "It's a decent sci-fi blockbuster, a visual effects master class and the best nature documentary you'll ever see," he writes in his review. 

In case it's been awhile since you last saw the original Avatar, here's everything you need to remember about Cameron's 2009 sci-fi tale.

Who are the Na'vi?

The Na'vi are inhabitants of the planet Pandora. They're blue, about 10 feet (3 meters) tall, worship a goddess called Eywa, and mate for life. In the original film, the Na'vi live in a jungle, though other clans of Na'vi live in other locations on the planet. The sequel takes us underwater, introducing us to some of those other Na'vi groups.

Why did humans come to Pandora?

The year is 2154 and Earth has run down its own natural resources. The main conflict of the movie arises because a group called the Resources Development Administration, or RDA, wants to mine a mineral found on Pandora called unobtanium (yes, really). In particular, there's a concentration of unobtanium under what the Na'vi call their Hometree, a tree that has significant cultural and spiritual significance.

How do humans become Na'vi?

Pandora's atmosphere is inhospitable to humans, so Earth scientists combined human and Na'vi DNA to create Na'vi clones. Humans can then remotely pilot those clones, which are called avatars. 

How did Jake Sully get involved?

Jake Sully is a former Marine who lost use of his legs. He ends up replacing his twin brother, who had a contract to go to Pandora and operate a Na'vi avatar, but was murdered. Jake pilots an avatar to infiltrate the Na'vi to spy on them, but he ends up sympathizing with this majestic race and being drawn to the beguiling Neytiri, the princess of the clan.

Is Pandora safe in the end?

In the final conflict between the humans and Na'vi, Pandora's wildlife essentially comes to the rescue. It's thought this is because Jake prayed for help to Eywa. All the humans, with a couple of exceptions, get kicked off Pandora. 

What happens with Jake and Neytiri?

Over the course of the movie, Jake and Neytiri fall in love and commit to each other. Though he originally worked for RDA, Jake defects to the Na'vi and fights with them against the humans. In the back portion of the movie, RDA's Colonel Miles Quaritch (Stephen Lang), the villain of this operation, exposes Jake's human body to Pandora and is about to kill his avatar when Neytiri kills him with a couple of well-placed arrows. Jake is permanently transferred to his avatar. Though Quaritch dies in the movie, Lang is back for The Way of Water, and his character on IMDB is listed as Quaritch.

What about Dr. Grace Augustine?

Grace Augustine (Sigourney Weaver) plays a scientist who spent years working with the Na'vi. She also works with RDA, on the avatar project. Like Jake, she finds herself torn between the humans and the Na'vi. Ultimately, she decides to help the Na'vi but ends up getting shot in an escape attempt. Though the Na'vi try to heal her and permanently transfer her into her avatar, she dies. Weaver is returning for the sequel, but her character is listed as Kiri. 

Where does the sequel pick up?

Though we don't have full details yet, from the trailers The Way of Water seems to take place at a point in the future when Jake and Neytiri have children. They also seem to have left the jungle and to have met another Na'vi clan that lives near water. But even if the humans scampered off last time, they're back to cause more trouble.