曾几何时,云端的巨人依靠通天豆荚来至大地,他们横行肆虐,吞噬人类,祸害无边。多亏勇敢机敏的埃里克国王将巨人赶回老家,巨人的传说从此越传越神,流传甚广。自幼深深为巨人故事所吸引的穷人家青年杰克(尼古拉斯·霍尔特 Nicholas Hoult 饰)进城买马,偶然遭遇一名被皇家卫队追捕的僧侣,他更在慌乱中用马换了对方手中的豆荚。夜幕降临,暴雨突至,不愿将毕生幸福付与他人的公主伊莎贝尔(艾莉诺·汤姆林森 Eleanor Tomlinson 饰)趁乱出走,辗转来到杰克家中避雨。正当他们聊天之际,被雨水浸透的豆荚突然发芽,豆茎疯长,直达天际,将困在屋中的公主带入云端。 为了找回公主,杰克自愿加入国王组建的营救队伍,等待他们的却是耳熟能详的传说里的巨人……Sent to the market by his uncle to sell their horse and buy thatch for their roof, Jack meets the beautiful Princess Isabelle whom he rescues her from ruffians. He returns home only with a handful of beans given to him by a monk who claimed they were sacred but that does little to impress his uncle who tosses them away. In the night the Princess arrives having run off to keep from marrying Roderick who is clearly only interested in becoming king. Soon the beans take root with a giant stalk carrying away the princess and Jack's house. He soon sets off on an adventure with the king's guards to rescue the princess only to find that a mythical land filled with giants really exists.