The doorway: Other world.

Three teenagers are drawn through a doorway into another world after setting up a series of crystals as instructed in a book they found in a reputed haunted house.

The world looks barren of intelligent life until a little person suddenly comes upon them warning them that they need to follow him. He leads them to an underground town where they are introduced to the leader, a very tall man named Kor.

Kor tells them of the meteor shower that nearly destroyed their world and of the big meteor that now sits at the decimated power plant emitting toxic radiation that keeps them from living above ground. Since the teenagers are nearly immune to this type of radiation he asks that they make a trip to the meteor to set a bomb to destroy it. The kids reluctantly agree.

The teenagers cross a dangerous landscape inhabited by large snakes, and giant scorpions armed with double stingers, and dogs that follow mysteriously at a distance, but do not attack. They make it safely to the meteor and set the bomb. Then something goes horribly wrong. The timer on the bomb shoots up to only minutes. The three run for the only cover that they see. They manage to get behind some stacked containers. The bomb explodes and the teenagers are temporarily buried under debris. They are lucky to be alive. But the explosion changed them. They soon discover that they have attained super powers. They soon realize that they will need these powers if they hope to stop an emerging threat.