Lina Inverse, the main character, is a fiery red-head sorceress whose one goal in life is to run around the world destroying just about everything in her way so she can have LOTS of money, and get cool stuff.
Gourry Gabriev, her sidekick, is a blond-haired "warrior" type guy who just happens to have no intelligence at all. He means well, but he's just plain stupid.
Zelgadis, the "serious type," is a sorcerer that happens to have his body gnarled into that of a golem. His skin, hair, etc...all made of bluish-green metal and stone.
Amelia begs her own category: a dark-haired "Justice Freak" whose obsession with Heroes and Justice is...well...disturbing.
The four journey about, and nothing but the most bizarre, clever obstacles stand in their way: Being forced to act in a bad play, Lina's forced making-out with a fish, Gourry always changing the subject to the flatness of Lina's chest, or even fighting the Devil himself, the four have it rough.
For the best viewing, it's recommended to watch the show in Japanese, because the voice actors have professional training (it's like actual on-screen acting there), and thus portray their characters PERFECTLY. The English dubbing is O.K., but it's just a good idea to watch it in the original language, because it's meant to be that way.