The Road… traverses Time—Time past, Time to come, Time that could have been, and Time that might yet be. Some people have the ability to access the Road and travel it from Time to Time and world to world.
The player characters, experienced and somewhat well known, hear rumors and travelers' tales about a distant area being overrun by dragons (or other terrifying monstrosities). The locals have sent them a message, begging for heroic aid.
When they investigate, they discover that nothing of the sort is going on. It turns out that a group of thieves wanted them out of the way so that they could rob them (or someone who would normally receive their protection).