I only liked, didn't love the first book in the Gallagher Girl series. The first book was cute and an enjoyable read but the spy stuff was campier than I'd expected - to compare it to TV shows, it felt more like a Chuck than an Alias or a 24. The thing is, I grew to love Chuck for the same reasons I think I have grown to love the Gallagher Girls. The author doesn't really try to make spy stuff realistic (the gadgets and tools feel more like magic than anything science could actually produce) but that should just be treated as a fun sideline to what is becoming a series with characters that you love and really care about, a world that is becoming more complex and interesting and a plot line that stays emotionally true to the characters.
Cross My Heart...starts off with the main character Cammie dealing with the ramifications of what she did in Book 1. Yep, there's no magic reset button and although you can read and enjoy this book without reading the first, readers who have read Book 1 are paid off with a continuing story and answers to some of the questions they were left with.
So join Cammie and her friends as they try to to discover who or what the mysterious Blackthorne is...and Cammie meets a boy who she might be able to share her secrets with. (And I must say, will have all teenage girl readers swooning over him). If you're looking for a teen book series to get into, I recommend this one...they're getting better all the time.