She comes to him in a dream, this spirited, red-haired young woman named Ruby Sparks (Zoe Kazan), who is cute and funny and smart (but not in an annoying, bookish way) and even likes to play with his adorable dog. Calvin (Paul Dano) falls in love with her instantly, and when he wakes up, he starts to write about her. Finally, the inspiration for his long-delayed second novel has arrived. At night, Calvin dreams of Ruby; in the day, he writes to spend more time with her.

And then, one morning, he walks out of his bedroom, and she’s standing there in his kitchen, making him breakfast. The best stuff comes early in Ruby Sparks, which was written by Kazan (granddaughter of Elia) and directed by the husband and wife team of Jonathan Dayton and Valerie Faris ( Little Miss Sunshine). Calvin isn’t seeing things: Ruby is really there, in the flesh, and other people can see her, including his older brother Harry (Chris Messina), who had started to wonder if Calvin was going crazy with all this talk about his imaginary girlfriend.

“Quirky, messy women whose problems make them endearing aren’t real,” says Harry, who is happily married but admits he sometimes looks at his wife and has no idea who she is. The premise of Ruby Sparks, which is a clever riff on Pygmalion, explores what happens after Calvin magically conjures up his dream girl (the how is never explained) and discovers that he can make her do anything he wants simply by writing it into his novel. If she’s being too clingy, he can fix it with “Ruby needed some time to herself.” If she’s being too distant, he can change that with “Ruby missed him terribly.” After a while, Calvin decides it is unfair to control Ruby in that way. He promises Harry, the only one who knows his secret, that he’s locking away his manuscript and will never “write” her again.

But how long can he hold out? Ruby Sparks poses some intriguing questions about what men want from women and the compromises people make in order to keep their love for each other going. When Calvin takes Ruby to meet his mother (Annette Bening), he is struck by her relentlessly happy bond with her new husband (Antonio Banderas) and wonders how they manage to keep the excitement from seeping out of their marriage (their method: drugs, pool parties and a hippie lifestyle).

Calvin, who was perpetually single and lonely before Ruby entered his life, doesn’t make many demands on his girlfriend. But inevitably she starts becoming restless and bored of their routine (“You don’t have any friends,” she observes coldly one night). The temptation to pull out his novel and write Ruby a new attitude grows stronger. And that is where the movie sadly veers off-track into allegory. Instead of forcing Calvin (wonderfully played by Dano) to grow up and confront the complexity of his relationship, Ruby Sparks opts for a seemingly darker but ultimately easier resolution, one that involves magic and fantasy and the sort of neat, happily-ever-after finales that only exist in movies. Just when Calvin was starting to learn just how messy true love can be, Ruby Sparks wimps out on him. The dog really is cute, though.