I just absolutely cannot think of a solution for a story!?

The story has to do with this prison in the arctic circle where all these monster-y things are kept because they want to take over the world and kill all the people because they hate global warming or something... They're working with this organization and have promised them power if they can figure out how to open the jail. There is a key, which they have found, and are on their way to unlock the prison. My main character's parents have been captured and are being held somewhere because of how much they know about it. There are also lots of other groups of hidden creatures, but they don't mind the people as long as they aren't disturbed. I've been trying to think of a solution and I have some bits and pieces but it's not working very well. Do you have anything, even just an idea, to suggest for a solution to the story? (there won't be a sequel, so no cliffhangers.)