Stoorworm's Sibling

Xandria, Matthias, and Gobed discover a kingdom that has been completely deserted. Xandria and Gobed enter the domain while Matthias gets sucked back in time. Xandria discovers that the kingdom has been cursed, while Matthias finds it thriving and filled with people. However, the area is under attack from a dragon. Somebody can only slay the beast if it happens in two different time frames. Can the three of them stop the dragon before the kingdom is forever cursed?