TI-JEAN and His Brothers," at the Sanctuary Theater, is made of the eternal stuff of folksongs and legends. Derek Walcott's play with music blends elements from ancestral myths, the David and Goliath story, Shakespeare's "The Tempest" and "The Wizard of Oz," and uses the campfire story form to help a spoonful of politics go down.

The devil is living on a tropical island and he's feeling brought down. So he offers a challenge to the poverty-stricken family of young dreamer Ti-Jean and his two brothers, the arrogant, musclebound Gros-Jean and the pridefully intellectual Mi-Jean. Each brother gets his shot at performing Sisyphean tasks for the devil, drawn here as a wicked white plantation owner. The one who succeeds in making the devil feel anger or any human emotion will be richly rewarded. Of course, he who fails will be devoured by the devil's vampire minions. (Three guesses which one wins.)

It's apparent that a great deal of effort has gone into this production, but director Michael Oliver's decision to let each performer stretch out hampers the show's simplicity and its effectiveness. "Ti Jean" would benefit greatly from a quickened pace and more play and less work from the actors. What should be a sprightly, fanciful folktale is a ponderous 21/2- hour ordeal.

Clayton Lebouef, the show's only real singer, offers a charming performance as Ti-Jean and gives the second act a much needed lift, and Terry Lang menaces and amuses as a husky-voiced devil. Michael Oliver's primitive environmental set is as colorful as a rainforest, and the five-piece orchestra adds a beguiling calypso lilt to Walcott's sparse melodies.

The true stars of this production are Jack Guidone's remarkable masks. Combined with Elizabeth Bruce's elaborate costumes, the brilliantly colored and detailed masks -- transforming actors into giant frogs, fireflies, birds and demons -- are grotesque and fantastic enough to save this humble show.