宋末蒙古蒙哥(gē )大汗(hàn )南下侵宋,途(tú )中遇到飞天炮阻击身(shēn )受重(chóng )伤。后法王虽偷得飞天炮,然蒙哥伤(shāng )势加(jiā )重,只得撤兵。返程中被忽必烈偷袭(xí ),逃入(rù )雪山。蒙哥感到命不久已,写下血书(shū ),传位(wèi )尚年幼王子海都后自尽。大雪山中(zhōng )人马(mǎ )走散,飞天炮和血书失(shī )踪,海(hǎi )都逃出雪山(shān )后遇到受伤的法王,原(yuán )来他(tā )受到中原三(sān )大高手的袭击,他们一(yī )起返(fǎn )回雪山找寻(xún )其它队伍但是雪山迷(mí )宫使(shǐ )他们放弃。与此同时三大高手也感(gǎn )无力(lì )进入雪山,将进雪山迷城的地图分(fèn )成三(sān )份交各人保存。法王带着海都勉强(qiáng )到达(dá )师弟银枪法王处,将海(hǎi )都托付给师弟后(hòu )毒发身亡。海都从此身(shēn )负夺(duó )回帝位的重(chóng )任。