The year is 1850. After fighting to help California become the 31st state of the Union, Zorro promises his wife Elena that he will give up his secret identity and live a normal life as Alejandro de la Vega. But now, the same forces that conspired to keep California from becoming part of the United States are plotting to unleash a threat that has been 500 years in the making -- a threat that could change the course of history forever. Only Zorro can stop it by taking on the most dangerous mission of his life. But, if he does what he must, will it mean losing Elena forever?