Winter is approaching, and the Fillyjonk, the Hemulen, Toft and others have travelled far and wide to visit Moominvalley to see the Moomins. But when they arrive, they discover the Moomins are nowhere to be seen. As they settle in to wait for their return, they start to realise that not everything is as it seems. The Moomins sleep through the winter. Or they did, until one day when Moomintroll wakes up to discover a world where the sun does not rise – and what’s that cold, white powder covering the earth? Alone and frightened, can Moomintroll learn to survive in a world so unlike the one he loves?