Sherry (Julie Delpy) leaves Don (Bill Murray) at the start of the film because he's afraid of marriage, children, responsibilities, etc. She doesn't want to be the next woman he dumps before moving on to another.

But she's not leaving him for good, she's cooked up a little plan with the well meaning but nosy neighbour Winston (Jeffrey Wright) an amateur detective, to teach Don the importance of a family and a strong long term relationship. A few days before she goes, she posts to Don's address, a letter typed on pink paper, in a pink envolope addressed in red ink. The letter, which is unsigned to confuse him, tells Don that he has a 19 year old son.

Winston, being in on the plan, is fairly certain that Don will share the letter's contents with him, if not he can go to his house and pretend to see it somewhere. If Don is unresponsive, Sherry and Winston will keep sending letters until he reacts.

Don is unmoved by the letter at first, he thinks it's a prank. We watch Winston's comical attempts to coerce Don on going on a trip around America to visit all of his old girlfriends from twenty years ago to discover who sent him the letter. There is only this explanation for Winston's burning curiosity to solve this mystery. Finally he's successful, and Don agrees to take the trip.

Sherry and Winston might not know exactly what it is that Don will discover, but they hope it teaches him a much needed lesson in love and life.

When Don returns to find another pink envelope with no proper postal address, only "Don" written on the front in red ink, he opens it to find out it's from Sherry. He takes it to Winston who makes a big show of analysing the handwriting on both envelopes, but I think he knows that Don knows it was partially a trick.

Don's trip down memory lane has left him a little shaken, and although he knows there is no son, he cannot help but feel kindly towards the young man he's seen both at the airport and outside the restaurant. He thinks Sherry's set the boy up for this trick, so he buys him lunch and talks to him, and starts to say "Look, I know you think I'm your father..." but of course, the boy runs away thinking Don's a freak. And Don, despite knowing the truth, feels dissapointed, because he wishes he had a son.

The story is about facing one's life and death too. Don has no legacy, nothing for the world to remember him by. He has a string of ex girlfriends and an IT company, but his personal life lacks much meaning and emotion. By contrast Winston's life is rich with happiness, and the full range of emotions because of his five children and wife. The bright colours in Winston's house are not so much Ethiopian symbols as they are to show the contrast between his richly colourful life and Don's drab and grey life.

The wilted pink roses in Don's house are a symbol of lost love and dying hope, the bright pink flowers he takes to all of his ex girlfriends show that with each passing day, he's learning something else, and the light is coming back to his life. By the time he meets Sun Green (Pell James) who gives him the loveliest boquet of all the one's featured in the film, the allusion is unmistakable. He visits his dead ex-girlfriend's grave and it's over there that he realises that he doesn't want to die alone.

The film is all about mementos. Laura Miller (Sharon Stone) may have a dead husband and a lolita for a daughter, but Lolita (Alexis Dziena) is the brightness of her life, the memento of her love. By contrast, Dora Anderson (Frances Conroy) and Penny (Tilda Swinton) are both unhappy without children. The photo that Don's taken of Dora as young woman is her husband's favourite, but he'll never know who took it. Don asks Dora if the pearls she's wearing are a gift from him, but they're not,there's nothing that she will remember him by. Carmen is unhappy to see him, clearly he'll never live on in her memories.

All this makes Don realise what the most important things in life are. Sun Green's kindness and the temporary bond he forges with the wandering kid (Mark Webber) are the lesson that Sherry and Winston wanted to teach Don.