For a futuristic grim gory setting. Probably powered by some kind of dilithium battery or something similarly awesome. Anyways, basicly a big drill sticking up from a hilt that you primarily use for skewering enemies painfully and drilling through armor.
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).