The Duffer Brothers have confirmed that production for season 4 of smash-hit Netflix original series Stranger Things is underway and have shared a little taste of what's to come with a snowy teaser.

The teaser, titled "From Russia with love...", confirms that Jim Hopper will return this season after his fate was left in question during season 3's finale. He's not dead -- but he is imprisoned in the snowy wasteland of Kamchatka and will face dangers both human and other.

At the end of season 3, David Harbour's character seemingly sacrificed himself. Theories speculated about whether he was dead, especially after an IMDB cast list did not include his name.

Meanwhile, back in the states, a new horror is beginning to surface, something long buried, something that connects everything….

Check out the trailer below.