A long time ago (some three to four hundred years), A mage living on a small island saw his island being eaten away by the sea. He decided to save the population of the island and his knowledge, so he hired a group of dwarven diggers to dig out a huge cellar below part of the island.
After that, a trench was dug out, all along the cellar and a metal band was placed around the area (measuring about 400 by 400 feet).
Once the trench was completed, many a crate of floating stone was carried into the cellar and finaly the island took to the air.
In the middle the wizards tower is standing about 160 feet high. From the tower, lines run down to which sails can be attached. These sails are the only means of propulsion.
Over the years, many of the island dwellers have left the island to find a place to live on solid ground.
Only the wizard and a small guard troop remain.
When the adventurers see the floating island, it is attacked by a huge number of goblins. Sails ablaze by the fire arrows that struck the sails by sheer luck.
Their choices include:
- Returning later (with more of the castle being overtaken by the goblins)
- Attacking the goblins flat out (however there are soo many, the players will then be over run before they even get near to the floating island)
- Attacking small groups of goblins and creating diversions , so they may get to the island and deffend the higher ground.
Rewards can be diverse. Maybe the mage is still there and will give them a proper reward.
Maybe the mage is gone, but the goblins have still left some valuables….
disclamer: I know the plot is lacking in back-ground on some points. This is intentional. I do not want to tie down the DM who uses this to my world.