Fans of the popular TV show have been longing to know what's going on in Hawkins, Indiana, since the second season ended with Eleven (Millie Bobby Brown) reuniting with her friends Mike (Finn Wolfhard), Lucas (Caleb McLoughlin) and Dustin (Gaten Matarazzo) after shutting the gate to the Upside Down once and for all.
But season two finished on a cliff hanger with an ominous shot of the eery world below Hawkins, with the Duffer brothers making sure the Upside Down isn't going anywhere anytime soon.
The new trailer for season three shows creatures from the Upside Down have made it past Eleven's gate, and appear to be terrorising an Independence Day carnival.
Big things are also in store for Lucas' little sister Erica (Priah Ferguson) who prepares to go on a "wild mission to save Hawkins from a dangerous and unexpected new threat".
The teaser also showed that other series favourites would be returning, including Hopper (David Harbour), Joyce Byers (Winona Ryder) and Steve Harrington (Joe Keery).
There will also be some new faces, including Mayor Kline ( Cary Elwes from the Princess Bride), Bruce (Jake Busey) and Robin (played by Maya Hawke, daughter of actors Uma Thurman and Ethan Hawke).
Stranger Things Season 3 airs this Thursday the 4th of July.