Early in this movie, free-spirit love-seeker Cristina (Scarlett Johansson) talks about a 12-minute movie she wrote, directed, and starred in (and now despises and can't watch) about how hard it is to define love. Her host in Barcelona quips, "That's an awfully big subject to handle in 12 minutes." Woody Allen then goes on to show that you can't really define it in 96 minutes, either.
Cristina is spending a summer is Spain with her best friend Vicky (Rebecca Hall). They agree about almost everything--except love (as a narrator efficiently explains). Cristina is freer, more prone to short term tempestuous affairs. She doesn't know what she wants, only what she doesn't want. Vicky knows exactly what she wants--traditional, stable commitment. Not so much passion as comfort and security. And she has that in her fiance, a very nice man with a good job who's not afraid of commitment.
In Barcelona, they meet Juan Antonio (Javier Bardem), a passionate painter with a crazy ex-wife Maria Elena (Penelope Cruz). He attempts to seduce them both, and over the course of the summer does. Vicky just for one drunken night that she can't get out of her mind. Cristina for most of the summer, which turns into a three-way with Maria Elena. And then...well, love is still not defined and despite all the sound and fury, everyone is exactly who they were in the beginning.
Woody Allen makes so many movies, stories like this seem effortless coming from him. And this literally looks like something a true master slapped together in a weekend, moving as briskly as possible from one scene to the next. I think his movies have increasingly become about his ability to effortlessly make movies. He now exists in a weird strata where he can impress without trying, but it's unclear if he'll ever inspire again.