The Power of the Dark Crystal is the name of it, to be released over 25 years after the original was, back in 1982.
John Henson wanted to make an epic “muppet” movie, mixed with live actors, and did so in the original The Dark Crystal. I have only watched it once since my childhood, but I watched a ton of times then. It was a great movie with a very good story. After all this time, I had no clue that a sequel was in the works, this time fronted by Jim’s daughter: Lisa Henson.
The new writing credits still list Jim among them, so apparently he did have an extended story. Here is a plot summary as listed on the movie’s production blog site:
Power of the Dark Crystal is set many years after the events of the first movie. Jen and Kira, the gelflings, are older and are reigning as king and queen in the Castle of the Crystal. After the Gelflings welcome a fiery. and unexpected visitor. to their castle they learn that the very existence of the U-mun people, who live in the searing heat in the center of the planet, is threatened by the death of their sun. There is apparently only one thing powerful enough to heal the dying sun – a shard of the Crystal.
The Gelflings refuse the request for a crystal shard, as breaking the crystal would disturb the peaceful surface world’s balance. But the desperate visitor takes matters into her own hands and steals a shard, making a hasty escape through tunnels deep in the bowels of the castle. The surface world once again falls into darkness – as the UrSkek split into Mystics and Skeksis. So begins the adventure of Thurma, a girl “made of fire”, who bands together with Kensho, an outcast Gelfling, in an adventure in the “inner-world” over the fate of the planet.
The movie is slated for release in 2008. Some rumors went around that it was being cancelled but they were recently dispelled on the blog:
“The Jim Henson Company remains committed to producing Power of the Dark Crystal. The film has not been “cancelled” or “put on hiatus” or any of the other rumored status changes that have been floating around. This film is an ambitious undertaking for us and it continues to move forward…We are grateful to the fans who support Power of the Dark Crystal and we are excited to make this new chapter in the Dark Crystal story a reality.”
– Lisa Henson, co-CEO of The Jim Henson Company & producer of Power of the Dark Crystal