A motif of sibling loyalty contributes to the theme about trust as a basis of relationships. Caleb and Bobby Gene best exemplify this motif. Bobby Gene frequently shows loyalty to Caleb by not tattling, by serving as a voice of conscience, and by guiding Caleb’s behavior: “If Bobby Gene hadn’t been there to stop me talking back to Mom, I don’t know what might have happened” (149). Caleb has mistrustful moments when he and Bobby Gene do not agree, but he accepts that Bobby Gene will always be on his side: “Even when he’s leaving me alone, we’re always sort of together” (175).

Caleb learns complex lessons about sibling loyalty over the course of the conflict surrounding Styx. At times, like on the train to Mr. Pike’s, Caleb identifies more with Styx in his thirst for adventure and idolizes his sense of control and power; when Styx leans out the train to feel the wind, Caleb does as well. This causes an epiphany: “Bobby Gene bit his lip, traying to look braver. We had been inseparable all our lives, but I was starting to see the difference between us. The way Styx challenged the world to a fight—it pulled me forward, leaving Bobby Gene behind” (179-80).