In 1919, six adventurous Brownies—Lulu, Minnie, Lottie, Agatha, Bernadette, and Beryl—discover an old lantern in Ashdown Forest with a cryptic riddle etched into its base: "Seek where the raven guards the past, beneath the stones where shadows last." Following clues to a raven-haunted monolith and a hidden stone circle, they unearth an 1859 surveyor's journal and smuggler's treasure. The journal leads them to a legendary healing spring, where they witness its miraculous properties first hand. Their findings attract local historians, revealing the lantern's ties to forest wardens and Napoleonic-era smugglers. Celebrated as junior historians, the girls return their discoveries to the village museum, proud to have preserved a piece of Sussex's past. As they gather around their campfire, the restored lantern's glow reminds them that the forest still holds secrets waiting to be uncovered—and their next adventure is just beginning.