Netflix has released the first teaser for Stranger Things 4, the upcoming fourth season of its breakout series, and it features a surprise reappearance of a fan-favorite character.

The teaser doesn’t reveal too many details about the upcoming season, but it seems like the promise that the series would be expanding its world beyond the town of Hawkins, Indiana, is correct: the trailer shows a group of workers building a railroad somewhere in Russia.

Spoilers below for Stranger Things 3

But the big surprise comes at the end of the clip. As many fans have already guessed based on the post-credit sequence in the final episode of the third season, Chief Jim Hopper (David Harbour) is back, despite appearing to have perished in an extradimensional portal.

Presumably, Hopper’s survival has to do with the latest supernatural meddling in the Upside Down, given that the Russians were previously shown to have a captive Demogorgon monster.

There’s no release date yet for the fourth season of Stranger Things, but with Netflix starting up the marketing campaign already, it likely won’t be long before the show hits the streaming service.