Prehistoric fantasy. 12-year-old Pitt and his pterodactyl pal Kantrop try to help their tribe. Stef promises Sariac a new hut for his birthday. Kantrop ends up hauling the stones for its construction on the flank of the mountain. To alleviate his burden, Pitt invents the wheel. But Kantrop's loads are doubled. Pitt prefers to free Kantrop from this brutal exploitation, so he lets him hide in the jungle, where the pterodactyl has to sharpen his survivals skills. Meanwhile, Pitt realises the building site is a volcano about to erupt!