Rose Morgan is a professor of romantic literature who desperately longs for passion in her life. Gregory Larkin, a mathematics professor, has been burned by passionate relationships and longs for a sexless union based on friendship and respect. They're two people with almost nothing in common, but fate, in the form of a personal ad and a meddling sister, brings them together. And without physical attraction to complicate matters, Rose and Greg become best friends and soon agree to an unconventional marriage built on intellectual passion instead of sexual heat. But when two people meet, marry, try to remain celibate and then fall in love, they realize they are courting chaos.