Your life was as happy as it could be, but last night some pesky knight stole your pet Princess while you were asleep. Go and kidnap her back!
As a monster, you can't wield weapons or armor. But you have your claws and lots of potions someone left over all the place. Quaff them and become stronger!
Fight your way to the princess before she can reach surface.
Now stop thinking and go after her!
Editors Note: There is an interesting post-mortem to read too.