A spring flood bursts a dam on the river and four young beaver friends – Marc, Denny, Vince, and Remy – are swept away by a whirlpool, along an underground river and into a huge dark cave.How to find their way home? A friendly plesiosaur helps the beavers reach the surface and suggests that they ask the wise White Salamander, who lives far away. On a journey filled with adventures the friends meet Alison, the cat, who joins them on their travels. Together they find White Salamander who tells the beavers to look for some builderite – a stone that can save their dam forever.But it’s long way to go, through unknown places full of mystery and danger. Will they ever find the builderite?The quest for the stone brings the friends to a snowy seashore, far away from their home. How to find their way back? The long journey is filled with dangerous adventures, mysterious events and strange encounters with tiny horses, enigmatic platypuses, enchanted elephants, glowing caterpillars and huge pterodactyls.Sometimes, it seems to the friends that they will never reach home. But they keep going.