Confirmed bachelor Don has just been dumped by his latest lover, Sherry. Don begins to resign himself to being alone and left to his own devices. However, he becomes compelled to reflect on his past when he receives a mysterious pink letter by mail. It is from an anonymous former lover and informs him that he has a 19-year-old son who may be looking for his father. Don is urged to investigate the contents of the letter by his closest friend and neighbor, Winston. Hesitant to travel at all, Don nonetheless embarks on a cross-country trip in search of clues from four former loves. Unannounced, he visits each of these women and finds that they hold new surprises for Don as he confronts his past.