Jet Li plays a despotic Emperor in 50 B.C. whose evil is punished by a terrible curse laid on him by wizardress Michelle Yeoh: he and his army are turned into to terra cotta for all time; that is, unless he is re-awakened which, of course, is where the O'Connells come back into it.

The story moves to the year 1946. When we find them, Rick (Brendan Fraser) and Evelyn (Maria Bello) are retired to Oxfordshire, England, having been spies for the British during World War II. They are bored silly and welcome the offer of "one last mission" from the Foreign Office. Their assignment: courier a precious artifact back to the museum in Shanghai, China from which it was stolen.

Back to Asia: China is in turmoil but Jonathan (John Hannah) owns an Egyptian-themed bar in Shanghai. Unbeknownst to his parents, now grown-up Alex O'Connell (Luke Ford) is following in the family business as a young archaeologist on a dig in north-central China. He makes the discovery of a lifetime: the tomb of the Dragon Emperor, which has been buried for millennia. A beautiful assassin (Isabella Leong) tries to kill him to keep the location secret but Alex prevails. The Emperor's monument is transported back to Shanghai where another plot is in motion: military zealot Anthony Wong intends to awaken the Emperor and aid him in the re-conquest of China and the raising of his terra cotta army of ten thousand clay warriors.

The family is reunited and high adventure ensues: crash landings, treks thru the Himalayas, Yeti, avalanches, Shangri-la, three-headed dragons, pools of eternal life, epic battles, a shape-shifting Jet Li...