What is the book "The Pact: A Love Story" about?

I have been looking for a good romance book lately and my best friend's sister recommended "The Pact: A Love Story" by Jodi Picoult. The romance books I have read recently that I really liked were, The Twilight Saga and "This Lullaby". I've read some others like The Princess Diaries series and The Sisterhood of the Traveling pants series, but they weren't really what I was looking for. So what is "The Pact" about? Is it a good book? Do you think I would like it?