The players reach a small, out of the way town. The people there are terrified and desperate. Their children are being kidnapped by small, strange monsters that come in big groups. If they ask around and agree to help they will be told of a nearby tower in which strange lights can be seen at night. If they decide to stay at the town waiting for the monsters to appear, they will apear and the players should stop them from takeing some children. The town gives the players the task of searching and finding their children, because the children are always taken alive.
(the monsters are small, around one meter to one twenty high, and every one is different. They are all incredibly deformed, but are basicaly humanoid. Some sport psychodelic colours, some have beaks, or strange, furry body hair etc… they should be easy prey for the low level adventurers, in fact, to make a decent challenge the players, they should outnumber them 3 to 1)
Once they get to the tower they are met by a helpfull, elderly mage. He invites them to dinner and tells them about the monsters that have been ravaging the countryside. He also says the supersticious village folk blame him. The food has sleeping poison in it (he is immune to it, so he serves himself from the same plate). If they refuse or are agressive towards him, he calls his minions (make him completly insane, and archetypical, cackling etc… it’s the only humorous note in the whole adventure) Between him (his spells) and his small monsters he should subdue the adventurers (use spells like sleep, or try to stun them). If they win (make sure they have to kill almost all of the monsters to do so), and capture him (remember, his monsters are responsible for the kidnapping, he must know what happened to the lost children) read the conclusion of the adventure.
If not, they end up in a prision cell and the wizard tries some terrible experiment with one (bubbling cauldrons, etc). They can observe the wizard from their cells. The walls are lined with similar cells, full of monsters. If they cannot escape by their own means, a monser opens the door for them and cowers.
This takes the players to the final showdown. In the final fight with the evil wizard, they capture him, and when he is asked where are the children, he lookes perplexed
When they insist, he suddenly sees what they mean:
“Oh, but you killed most of them!!! Don’t you see, you’ve ruined my plan!!”
Of course, the children are the “monsters” the players have been slaying throughout the adventure. What they do to the wizard, what they do with any of the surviving children, and what they tell the villagers, is entirely up to them…