On the trip, let them be attacked by bandits. Once the bandits are killed, let the leader have a silver snake ring, the head biting the tail. Its worth maybe 50 gold.
When they get to town, and they go to sell it, the merchant suddenly takes in interest in the ring. He gives them a price of two hundred gold! Later that day the merchant leaves in a hurry.
If followed, He disapears in the back of a scurvy tavern. When he comes out, he appears much calmer, and he begins to walk back to the bazzar...but he staggers. He can't speak coherantly...He dies (Do ya think it was...POISON?)
Later that day for no reason, a group of toughs (warriors) try to intimidate the party. Tell the PC's, they need to leave town, or it'll get rough, see?! The PCs should mop the floor with these yahoos.
The thugs know nothing (deffinately nothing about the ring). they were hired locally by a hooded man (in the scurvy bar, no less).
The real reason they were hired was to see the skill level of the party. The fight was watched by....The Cult of the Dragon!
Dun Dun Duuun!
The cult is in Archendale for its mercantile wealth. they need to shake down the merchants, but the locals aren't giving in to extortion. The bandits on the road were hired to harrass anyone entering Archendale. The local gov't is very good at ferreting out criminal activities. So now some lessons need to be given.
A merchant's children are kidnappped. A tavern is burned. Another merchant is brutally murdered.
The key to all of this is a snake ring. the cult doesn't want attention drawn to it, so they are framing the cult of Set!
If the cult of the dragon was known to be in the area EVERY adventurer worth his salt would be charging down to Archendale!
Its another reason they are so worried about the PCs: Adventurers mean trouble.
Now its time to throw in a twist.
let the PCs uncover a cult hideout, and save the kids. A cultist is among the dead. He has a pamphlet about the mad prophecies of the cult of the dragon. they also find a (planted) holy symbol of set.
OK so just as the PC's figure out who this is, now a party of Set warriors show up. Somebody is framing them, and Set isn't happy. The Setites idea of investigation is going to the nearest bar and beating information out of the locals. this brings the guard out fast. LOTS of giant scorpions get summoned, and a warrior turns into a minion of set (use the stats of an Ogre, but with a better AC-describe him as changing into a crocdile-man)
Things can really get messy here, and with luck you can blame it all on your PCs. My Pcs have been thrown out of more than one town for using fireballs in a wooden Inn!
And no one really likes Archenfolk anyway.