宋末蒙古蒙哥大汗南下侵宋,途中(zhōng )遇到(dào )飞天炮阻击身受重伤。后法王虽偷(tōu )得飞(fēi )天炮,然蒙哥伤势加重,只得撤兵。返(fǎn )程中(zhōng )被忽必烈偷袭,逃入雪(xuě )山。蒙哥感到(dào )命不(bú )久已,写下血书,传位尚(shàng )年幼(yòu )王子海都后(hòu )自尽。大雪山中人马走(zǒu )散,飞(fēi )天炮和血书(shū )失踪,海都逃出雪山后(hòu )遇到(dào )受伤的法王,原来他受到中原三大(dà )高手(shǒu )的袭击,他们一起返回雪山找寻其(qí )它队(duì )伍但是雪山迷宫使他们放弃。与此(cǐ )同时(shí )三大高手也感无力进(jìn )入雪山,将进(jìn )雪山(shān )迷城的地图分成三份(fèn )交各人保存。法王(wáng )带着海都勉强到达师(shī )弟银(yín )枪法王处,将(jiāng )海都托付给师弟后毒(dú )发身(shēn )亡。海都从此身负夺回帝位的重任(rèn )。