On Dec. 18, Harbour dropped out of the “Stranger Things: The Final Season Celebration” event at the Paley Center in New York City, where he was set to appear on the red carpet with his co-stars and then participate in a screening and conversation.

One Last Adventure: The Making of Stranger Things 5, directed by Martina Radwan, is “an inside look at the years of effort and craft that went into the final installment of the Duffer Brothers’ generation-defining series ,” per Netflix. It was produced by Angus Wall, Terry Leonard and Kent Kubena, and hails from MakeMake Productions.

Stranger Things 5' Sets New Year’s Day Netflix Viewership Record With Finale, Enters Most Popular List; 'The Great Flood' Makes Non-English Film List

The gate to the Upside Down has closed after 10 years and 5 seasons—but these films and series will fill the supernatural, nostalgic void left behind.

Netflix revealed the release date and trailer for One Last Adventure: The Making of Stranger Things 5, a behind-the-scenes documentary.

With a giant evil spider monster, mysterious briefcase and a whole lot of teary characters bidding adieu, “Stranger Things” has now become a thing of the past.