This review and others are posted at Read, Rinse, Repeat.
"Where She Went," the sequel to If I Stay, is a very different story, and not only because the sequel is narrated by Adam, rather than Mia. If you read "If I Stay," (and if you didn't, I highly recommend it), you know that it ended with an incredible cliffhanger, and here with the sequel, we have the resolution.
Maybe Gayle Forman has more of a knack writing romance from the male perspective, but I have a much better sense of the (former) love between Adam and Mia in this book than I did with Stay. I just didn't really get it when Mia narrated, but with Adam, I could feel his love, his heartbreak, and his longing.
As the title indicates, we learn what happened to Mia during the three years after she squeezed Adam's hand in the hospital bed until their somewhat chance encounter after her concert at Carnegie Hall. Mia is now a famous cellist, and Adam is a rock star with an actress girlfriend and constantly hounded by paparazzi. (A little unrealistic, but let's go with it.) Mia disappeared soon after her recovery and rehabilitation, leaving a devastated Adam in her wake. Adam is still tortured by Mia's decision, and we feel it on every page. The tension between the two is palpable, and neither one is willing to broach the topic of their break-up. When Adam finally explodes, we readers, along with Adam and Mia, can finally breathe. The wall between the two is shattered, and the rest is just...beautiful.