Foil
Character Role Analysis
Cassie/Ringer
Cassie and Ringer have a lot in common. They're both tough-as-nails teenage girls with enough smarts to have survived the alien apocalypse. What's interesting is that they go about solving problems in two totally different ways. "If something goes wrong, don't overthink, Cassie," Evan tells her."You have good instincts; trust them. Thinking through every step is fine if you're playing chess, but this isn't chess" (76.20).
Ringer, on the other hand, is all about playing chess. (It's her favorite game.) Her analytical style of thinking is what leads her to the realization that Vosch and other personnel at the military base are actually aliens posing as humans. What's the takeaway? Both modes of problem-solving—gut checks and analysis—are equally valid. They're just two different ways of looking at the world.