In 18th-century Paris, Jacob Cerf is a Jew, a peddler of knives, saltcellars and snuffboxes. Despite a disastrous teenage marriage, he is determined to raise himself up in life. More than 200 years later, Jacob is amazed to find himself reincarnated as a fly in the Long Island suburbs of 21st-century America. Thanks to his arrival, the lives of a reliable volunteer fireman and a young Orthodox Jewish woman nursing a secret ambition will never be the same.