Summary
The book opens with The Wheat, a chapter centered on a group of unknown survivors who are hiding out in an old house, watching the seasons go by. A child comes to them, and appears sick so they take him in. The child has a bomb waiting to detonate, however, in his throat that is activated by CO2, or another person's breath.
When a woman examines the boy's throat and breathes, she sets off the bomb, which takes the whole house and everyone with it. This is just another new tactic of the Others to kill the most humans possible. They have now weaponized children and made the most vulnerable humans the more destructive.
The Problem of Rats opens with a narration by Ringer, who is skeptical that Evan survived the blast at the army base. She wants to move on and leave the hotel where the squad has been camped out. We get to see Cassie from her perspective and find that Ringer is sympathetic to her, but doesn't like her.
She thinks Cassie is endangering everyone with her lovesick desire to wait for Evan. Ringer is attached to Teacup and talks with her about not being soft so that they can survive longer. Ringer and Ben continue their flirtation. Ringer is concerned about Ben, who still suffers from an infection in the bullet wound Ringer gave him in the last book so that he could infiltrate the army base and get Sammy out.
Ringer walks in the woods, looking for the nearby caves in order to see if there are any people living there that can join the squad. She encounters a Fifth Waver who was shot with a gun that had a silencer on it. Ringer worries that a Silencer is nearby and she goes on high alert.
She grabs the pellet from the dead kid's body and puts it in her cheek in order to make herself less visible to other Fifth Wavers that may be lurking nearby. Ringer senses that she is being watched and becomes very paranoid. Ringer shoots the intruder before reminiscing about a conversation with Cassie at the hotel.
She doesn't understand Cassie's remorse over the Crucifix Soldier she shot out of fear that he was a risk that would get her killed. Back in the present, Ringer realizes that she shot Teacup, not a Silencer.
Analysis
The first chapter shows the reader that there are in fact other humans out there in the world. The squad is not the only surviving band, but they may be the one best prepared to fight - at least that we've met thus far.
The second chapter also lets us see into the mind of Ringer. Previously an enigmatic character, the reader can now understand Ringer to a much greater degree. She is sensitive, kind, caring, and highly intelligent. She hides all of these qualities under a mask of harshness and bravado that has helped to keep her alive thus far.
We also see that Ringer loves to play chess and is an accomplished strategist. However, her cold and calculating manner puts the people she loves in danger even when she is trying to desperately protect them.
Ben reminisces about how there may be a time after all of this when schoolchildren will learn about the waves and the Others, and then a tardy bell will ring and everything will be normal again. Cassie clings to the hope that Evan escaped in an escape pod. Ringer continues to distrust Evan, wondering why a virtual being needs a physical body and planet. Something doesn't add up for her.
Teacup follows Ringer into the woods even though she was told not to, and is accidentally shot by Ringer. This puts Ringer in an impossible situation, but after weighing the odds in her typically logical fashion, Ringer decides that Teacup's best chance of survival is to be captured by the Others, so she lets their helicopter find them. She doesn't run or hide but goes willingly, thus showing how much she also cares for Teacup.
