The 7 signs. Where do I start?! This is a great book that I would give to anyone that is a fan of action, suspense and chases. It is about 7 kids from different countries who are sent strange symbols predicting an attack on each of their countries! It is fast-paced and the final showdown in book 7 is amazing! Each of the 7 books deals with the attack in one of the countries - Egypt, USA, Greece, South Korea, Columbia, Australia, and Antarctica.
My favourite of the 7 books was Killswitch which is number 4 and based in South Krea. This was my favourite because they have a theme park run and made entirely by robots. My favourite part involved JJ meeting Robot JJ because of how alike they were.
I would give this series to 9-13 yr olds because there is some violence and some slightly brutal deaths. There are also some scary scenes, although there is no swearing.
I would highly recommend you read this book and I hope that if you do you enjoy it!