Hildy enlists the help of her cousin Ruby and friend Spud to gather information and follow clues that thrust them into unexpected jeopardy from unknown adversaries. Despite Hildy and Ruby's worst fears when the clues point them into the depths of the underground mine, they must follow. Racing the clock to save an injured boy, the three friends make their descent into the greatest danger they have ever faced.
An "accident" that wasn't an accident, a boy who won't give up, unstable dynamite and a ruthless trap will they see the light of day again?