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.
沃克家的四個小孩並不是故意跑去海邊的,他們答應他們的媽媽會安全地留在馬頭,禮拜五會準時回家泡茶。但是他們卻在大霧中跑到別人的船上飄向大海,若霧散去他們可以調頭回去馬頭,但霧不但沒有退散暴風反而來襲,讓他們駛向寒冷的北海。