When it comes to romantic comedy, everybody knows what's going to happen from the moment the curtain rises: Harry and Sally meet, they argue, they make up, they live happily ever after. So you have to give people a compelling reason to stay in their seats. Shakespeare employed a whole gamut of devices to keep the groundlings glued to the, er, ground, from fairy magic (A Midsummer Night's Dream) to oaths of abstinence (Love's Labors Lost). Deborah Zoe Laufer does it -- rather elegantly -- with a crystal ball. In Marin Theatre Company's world premiere production of Laufer's new comedy, a pair of star-crossed lovers get mixed up in the semantics of fate. A nerdy and desperate accountant (Darren Bridgett) appears on a fortuneteller's doorstep in Brooklyn Heights, N.Y., demanding to know whether he'll ever fall in love. The jaded seer (Julia Brothers) wearily looks into her client's future. She foretells one set of events, but as the play unfolds, manages -- quite inadvertently, and very much against the rules of augury -- to bring about another. Set designer Steven Coleman's take on a fortuneteller's parlor, with its layers of delicately colored gauze that shift mystically through the artistry of Jaymi Lee Smith's lighting, provides an otherworldly backdrop for the snappy colloquialisms of Laufer's dialogue. Energetic slapstick performances from Bridgett and Brothers and economical direction by Lee Sankowich convey both the foolish and the quasi-philosophical in the not terribly profound but nevertheless playful text.