Obtaining Zorua

To obtain Zorua you will need to have previously obtained the Fateful Encounter Celebi at an event for Diamond/Pearl/Platinum held prior to the release of Black & White. Using the Relocator Machine, transfer the Celebi you received into the game.

With the Fateful Encounter Celebi in your party, go to Castelia City gate, where you will talk to the people there until you trigger an event that will progress on it's own after you start it, and conclude with you receiving Zorua!