This one would probably be fairly straightforward, but with the amount of planar travel involved, chances are the PC's would come into all manner of side quests, distractions, or even needed detours as the game progressed.
The setting takes place in the never-ending war of Acheron. Three to five warriors, sent on a supply disruption mission by their commander, an alluded-to-but-rarely-seen bigshot who thinks he's all that because he's racked up a large kill count. The PC's were charged with commandeering a cargo launch perusing the River Styx loaded with essential supplies for the opposing army's troops that would undoubtedly turn the tide of war against the PC's commander.
When the PC's manage to hijack the boat, they soon discover that they have a completely controllable, perfectly manned boat that's capable of sailing the waters of the Lower Planes. And if it's loaded with enough cargo to supply an army, or at least a brigade of said army, chances are five people who stole the thing would have decent equipment on their hands.
Deciding to say "Screw the army, we're going AWOL" the PC's sail the launch through a tributary of the River Styx, forsaking their useless army. Why? Because they hear it's nice in Ysgard this time of year.
And then the mother of all roadtrips begins.
For the sake of having decent-sized magical firepower (and healing, for that matter), "warriors" in this case could also include
Druidic Avengers Battle Sorcerers and
This Cleric Variant with no cool name.Also, as this is a fairly straightforward RP, don't expect much storytelling. This is me, bored, winging together a swashbuckling adventure on the River Styx. Expect to sail (or row) through every part of the Lower Planes, dodging other members of your Army, the storms of Petitioners on every plane, Devils, Demons, Yugoloths, Demodands (Field Folio, for those unfamiliar), naturally annoying weather on certain planes, Lower Planar Dragons (Draconomicon), other lower-planes annoyances, and my favorite "run like hell" idea: Demon Princes and Archdevils (though only brief cameos that end up being more useful than Sh*t storm).