The Infinite Sea is the second book of The 5th Wave series by Rick Yancy. The book starts with the group of kids hiding in a hotel after escaping from Camp Haven. Everyone is there except for Evan Walker. Most of the characters think he is dead, but Cassie holds out hope that he is still alive.
Though the first book was told primarily in the voices of Cassie and Ben (also known as Zombie), in The Infinite Sea, we get to know more about Ringer through her telling of the tale as well. As the group holds up and starts to venture out on patrol, we also learn more about Evan and his background. But Ringer is the real focus of this book. Through her, we find out more about the Others, what they think of humanity, and how exactly their plans were laid out.
Full of intrigue and action, The Infinite Sea does justice to its predecessor The 5th Wave. Though again, there is an adequate and fulfilling finish to this book, it sets us up for the final installment The Last Star, where we will finally discover what the aliens had in mind with their particular type of assault. And if course, to find out what happens to the remainder of humanity.