Major spoilers for Stranger Things season 4, volume 1 ahead.

After three years of waiting, Stranger Things returned for its fourth season on May 27, just in time for fans to spend the bulk Memorial Day weekend glued to their TVs. The much-anticipated episodes followed the separated factions of the Hawkins gang six months after the Battle of Starcourt Mall, as they all prepared in some way or another to reunite and face off the ultimate villain of the Upside Down, the D&D-inspired sorcerer Vecna.

The humanoid monster terrorises the town of Hawkins throughout the season, psychically linking with teens who’ve experienced trauma and feeding off their fears before gruesomely killing them. When the villain sets his sights on Max (Sadie Sink), who is still grieving Billy’s death, the crew figures out a way to weaken the link through music therapy. They also discover that every time Vecna kills a victim, he opens a new gate to the Upside Down. Meanwhile, Eleven relives the repressed memories of her time in Hawkins Lab to remember how to use her powers after losing them in season 3.

Related article: Where Was ‘Stranger Things’ Season 4 Filmed?

In the final feature-length episode of Volume 1, we learn the true identity of Vecna, learning along with El that the orderly she had befriended during her time in Hawkins Lab was actually Henry Creel, test subject 001 of Dr. Brenner’s experiments (Eleven’s “Papa”), whose powers were subdued when the scientist couldn’t control him. After Eleven helped him revive his powers, he killed multiple kids and attendants in the lab massacre El had believed she caused herself.

The episode ends with a psychic battle between Henry Creel/One and Eleven, who refuses to join him in his goal to purge humanity. El wins the battle, by accessing memories of both sadness and love, and sends the villain into the Upside Down, creating the first gate in the process. As he descends into the dark dimension, One is struck by lightning and his appearance changes, with him also growing tentacles like the black widow spiders he admired. He is now Vecna, the ultimate Big Bad, who’s working to unleash the monsters of the Upside Down and destroy the human world.

Fans were left shook after the jam-packed episode:

Especially with the big Vecna/One/Henry Creel reveal:

Many now have “Running Up That Hill” stuck in their head:

And everyone’s realising we now have to wait for Volume 2:

This article originally appeared in Harper’s BAZAAR US