The summer-set third season of “Stranger Things” is headed to Netflix on July 4th, and at MCM Comic Con over the weekend, star David Harbour promised an emotional journey.

“Eleven is growing up and I think that’s the terrifying thing for Hopper. He doesn’t like the idea of his baby daughter hanging out with boys. So the season starts with him a little bit uncomfortable,” Harbour told the crowd at the event. “His daughter is becoming a teenager and beginning to find herself, so that’s scarier for Hopper than any Demogorgon creature that he’s going to have to deal with.”

Harbour continued, “You get to see a lot of that throughout the season and it’s very unexpected what happens in the end and it’s very, very moving.”

“I think episode eight is the most moving thing we’ve ever shot.”

Thanks to Digital Spy for the quotes.

Returning for Season 3 are Winona Ryder as Joyce Byers, David Harbour as Chief Jim Hopper, Finn Wolfhard as Mike Wheeler, Noah Schnapp as Will Byers, Millie Bobby Brown as Eleven, Caleb McLaughlin as Lucas Sinclair, Gaten Matarazzo as Dustin Henderson, Cara Buono as Karen Wheeler, Natalia Dyer as Nancy Wheeler, Charlie Heaton as Jonathan Byers, Joe Keery as Steve Harrington, Dacre Montgomery as Billy, and Sadie Sink as Max.

Cary Elwes, known for both Princess Bride and SAW, will play a character named Mayor Kline, while Starship Troopers, The Frighteners, and The Predator‘s Jake Busey will play a character named Bruce. Maya Thurman-Hawke, the daughter of Uma Thurman and Ethan Hawke, will play an “alternative girl” bored with her mundane day job. She seeks excitement in her life and gets more than she bargained for when she uncovers a dark secret in Hawkins, Indiana.

Francesca Reale (“Haters Back Off”) has been cast in a major recurring role as Heather, a popular lifeguard at the Hawkins Community Pool who becomes the centerpiece of a dark mystery.

Season 2 actress Priah Ferguson, who played Lucas’ scene-stealing sister Erica, has been upped to a series regular. She’ll return with an army of her own friends. No longer content with sitting on the sidelines, Erica finds herself on a wild mission to save Hawkins from a dangerous new threat.

The series is created by The Duffer Brothers, who also serve as executive producers and directors along with Shawn Levy (who also directs), Dan Cohen and Iain Patterson.