What if a therapist had a patient that revealed every aspect of her love life? And then later, what if the therapist realized that the patient was dating her very own son? This is the concept behind Prime, a movie that loses a lot of steam later in the film because it runs out of story to tell. Uma Thurman (Be Cool, Kill Bill Vol. 2) gives a surprisingly good performance that is emotionally rich, while Meryl Streep (Lemony Snicket's A Series of Unfortunate Events, The Manchurian Candidate) takes the opposite approach, going for broad comedy. The best parts of the film come when Streep's Lisa Metzger slowly begins to realize that Rafi Gardet (Thurman) is seeing her son David Bloomberg (Bryan Greenberg, The Perfect Score, A Civil Action).

Gardet is newly divorced and nearing forty. She worries about meeting men, until she meets Bloomberg. He seems far too young for her, but the happiness he brings her is a good, if not transient thing. Ironically, Metzer encourages Gardet on proceeding with this fling, fully expecting it to be short-lived. Worse, Metzger and Gardet have no clue about the connection they now share. Metzer and Bloomberg share different last names. Bloomberg lies about Gardet's age to Metzger, and Gardet lies about Bloomberg's age to Metzger. Metzger refuses to meet her son's new girlfriend because she is not Jewish.

Nevertheless, soon Metzger realizes what is happening, and it horrifies her. First, she needs to decide whether to tell Gardet. She struggles a bit with the ethics of the situation (though not much; after all, this is a comedy), before deciding to say nothing. Worse, she has to listen to intimate details about her son's sex life. Eventually, things come to a head, and then writer/director Ben Younger's (Boiler Room) turns boring. By going this route, the characters are less interesting, the story is very predictable, and Prime becomes like every other romance movie.

It's better to simply watch the very different performances of Thurman and Streep in the beginning. Streep's reactions, especially when Gardet shifts the conversation to sex, is very funny. It's also very hard, since Streep cannot ham it up, lest she looks too buffoonish. Here, she is believable as a doctor trying hard to help her patient while trying not to vomit. Thurman is luminescent. She looks fantastic, and her character alternates between vulnerability and strength. Gardet is happy with her career and her life, but still wants somebody to complete it. She is realistic about the low probability of the success of the relationship, which makes it harder when it actually begins to succeed. Younger's script is full of emotional highs and lows, and Thurman hits them all with aplomb. The one low spot is Greenberg, who doesn't stand a chance acting against heavyweights Streep and Thurman. Yes, he looks cute, but comes off as a bit bland. At the beginning of the film, he is slightly endearing and throws out some witty lines, but it's not clear why Gardet would stay with him for any extended amount of time.