'Stranger Things' Season 4 teaser revisits Eleven's past

May 6 (UPI) -- Netflix is giving a glimpse of Stranger Things Season 4.

The streaming service shared a teaser for the season Thursday featuring Millie Bobby Brown as Eleven.

The video appears to revisit Eleven's past at the Hawkins National Laboratory, a facility for children with special abilities. The sinister Dr. Martin Brenner is heard addressing a group of children as the camera zooms in on a door with the number 11.

Brenner then asks, "Eleven, are you listening?" before the camera cuts to Eleven gasping & opening her eyes.

Netflix released a Season 4 teaser in February 2020 that showed Jim Hopper (David Harbour) is alive but ended up at a Soviet prison camp.

Netflix has yet to announce a premiere date for Season 4, which was delayed due to the COVID-19 pandemic. Gaten Matarazzo, who plays Dustin on Stranger Things, said in an interview on The Tonight Show starring Jimmy Fallon in April that the season will be the show's scariest yet.

"That's the one thing that I've noticed. I was reading it, I'm like, 'They're going for it this year. That's pretty cool,'" he said.

In November, Netflix added Robert Englund and seven others to the Season 4 cast.

Stranger Things stars Brown, Matarazzo, Harbour, Winona Ryder, Finn Wolfhard and Caleb McLaughlin.