Adaptation of the science fiction short story by Jack Finney:

Scotty Corrigan, an engaged thirty-something, purchases an antique desk and finds a letter written in 1863 by its original owner, Elizabeth Whitcomb. Intrigued by her wish for ""a love that burns like fire and moonlight,"" Scotty playfully ""answers"" the letter—and is astonished to receive a reply. The extraordinary correspondence continues, and Scotty starts to question his commitment to his fiancée. Then he discovers it's not too late to alter the course of Elizabeth's life, as well as his own.