The kingdoms of the Stone World

Senku, Taiju and Yuzuriha are well on their way to crafting gunpowder when they spot smoke far off in the distance. Convinced that it's a sign of other humans, Senku takes a huge risk by sending up a smoke signal of their own. Meanwhile, Tsukasa is determined to stop their progress on gunpowder, and his arrival on the scene could spell the end for our heroes!.