Pirate Attack
The Pirates:
The pirates have been plundering the local islands and villages and have ambushed any ship foolish enough to venture forth into the open seas. Even the smugglers aren't safe from these attacks. As the ships have become more careful and the towns have become more watchful, the pirate attacks have become even bolder, with many fearing for a large attack in the near future.
The pirates would have a large ship, possibly included with a small portion of the town for them to loot. They would also have several smaller ships ranging from the size of a rowboat to a raft to a ship like the one included in Lake-town Chase. They could also possibly have a treasure cave or land based hideout.
The Pirate Hunters/Villagers/Smugglers
Fearful for their valuables and lives, the villages have banded together against the threat of the pirate crew. Even the smugglers have joined, as they have also been looted by the pirates. The new team has sworn to hunt down the pirates and bring them to justice. They operate from a smuggler's boat (smaller than the pirate ship) which has been converted into a war ship disguised as a trade ship in order to lure the pirate fleet to them and capture them. (The ship would be able to be customized into any of these three modes.)
The Pirate Hunters' main base would be their ship, and some other sets could include small skirmishes with the pirates. Parts of the town could also be included as the site for these battles. Hidden caves and jails to contain the pirates could be included with a pirate or two to break out of prison.
To summarize:Pirates vs. Pirate Hunters.