Classics, modern fiction, non-fiction and more. Written for secondary and adult students the Oxford Bookworms Library has seven reading levels from A1-C1 of the CEFR. The four Walker children never meant to go to sea. They had promised their mother to stay safely in the harbour, and to be home on Friday in time for tea. But there they are in someone else's boat, drifting out to sea in a thick fog. When the fog lifts, they can turn round and sail back to the harbour. But then comes the wind and the storm, driving them out even further across the cold North Sea...