While scrounging around the dump, a group of trolls accidentally discover the ingredients of gunpowder in a pile of Snakehammer's discarded contraptions. Now the explosions they are creating threaten the Meadowlands. When one of these explosions causes the destruction of the junior rangers' new clubhouse, Rowan disguises himself as a rock troll and heads for the dump, vowing to get to the bottom of the 'big bangs'. Meanwhile, the elves and the fairies have sent envoys to Troll headquarters, but they are captured, accused of spying and imprisoned. It is up to Rowan, who has now infiltrated the Trolls, to help them escape and destroy the last bit of the gunpowder, making the Meadowlands safe again.