Everything about Anna's life is secret. Her father works for the Branch at the helm of its latest project: monitoring and administering treatments to four genetically altered boys in a secret underground lab. There's Nick, Cas, Trev... and Sam, who's stolen Anna's heart. When the Branch decides to take the boys, Sam stages an escape. Anna is torn between following and staying, but her father tells her to go, making Sam promise to keep her from the Branch. They flee, but none of the boys remember anything about their past lives. Now on the run, Anna discovers she might be connected to Sam in more ways than expected, and if they're going to survive, they'll have to piece everything together before the Branch catches up to them.Altered is an exploration into the past while on the run from those who want to control their future and use them as tools, a thriller that circles around a group of teenagers on the run from a secret group who performed experiments on them. What was done to them? What have they forgotten? What is the truth? All they can do is run, run and search for the missing pieces, and hope they're the ones who can run faster.For some reason, before I started reading I thought this was going to be vaguely dystopian and was pleasantly surprised to find that it wasn't. Instead of a dark and dismal futuristic setting there's a possible present day setting, maybe a little technologically advanced with the semi-military group and their experiments but that was it.A book like this needs tension, it asks for it, but I didn't feel that there was enough tension until about a third of the way through the book. From there to the end, it was fast-paced. No one really knows what they're looking for, only that it's out there and they have to find it before the Branch finds them and locks them away.The author has crafted a very interesting group of boys, each with their own quirks and traits that help them get out of tough situations. Anna as well, she's like a mother hen wanting to take care of her boys, because they are her boys, in a sense. She cares about them more than anyone. She also has a stronger connection with Sam than with Cas, Trev, or Nick.There was a plot twist or two that I expected, but there were more that I didn't expect which made reading it interesting. As the first in a series about characters searching for forgotten memories, it leaves more questions unanswered than answered, but I'm looking forward to Anna and the boys' search to answer those questions and to uncover more secrets in their past.