Sylo is about Tucker, a boy who moved to Pemberwick Island five years ago. He has been friends with a boy named Quinn ever since he moved. Now Pemberwick Island is under a quarantine for a disease which he thinks is caused by a steroid called Ruby. Tucker thinks it is outrageous when the islanders' cell phones and internet stop working. This looks suspicious, but his friend shows him a program which is always streamed live at 6:00 PM. Now it has been prerecorded for them. They realize something more dangerous is stirring on their little island, and that is the biggest surprise for everyone.
This book is very interesting and has many mystery aspects. People aren't allowed to leave the island, people just disappear into thin air, and nobody has figured out why they're trying to quarantine them. This book gets two thumbs up for keeping me entertained the whole way through. This book is pretty violent, but it is appropriate for middle schoolers.