Tunnels Book Two = Panacea

After Nikki arrived at her dad's, she was in for more than a few surprises. She found the tunnels to parallel worlds her dad created. She learned her dad got sick in one of those worlds, but which one? The search for a cure takes her to strange worlds. Some are horrific, others are beautiful. Nikki is surprised to learn that a catastrophe in her world can cause a splinter world to develop, similar, yet different. The main thing she knows is the cure must be found, and if it is, the tunnels have to stay open. Humans in the world Nikki knows have destroyed so muc, that someday it may become uninhabitable.