Jonathan Grisby, the 12-year-old protagonist, harbors a dark secret that causes him to feel guilt and shame throughout the novel. While Jonathan’s unabating guilt dominates his personality through much of the novel, his transgressions are not as bad as he has led himself to believe they are.

Jonathan admits that he was an arsonist in the past. His unhealthy fascination with fire indirectly led to his sister’s death. Furthermore, at Slabhenge, Jonathan convinces the other boys not to report the adults’ deaths and even comes up with the plan to hide the bodies in the freezer. However, the guilt that Jonathan feels over his past behavior reveals him as a redeemable character from the beginning of the novel.

One of Jonathan’s major character traits is curiosity. His curious mind leads him to explore Slabhenge and discover the library and librarian. The other boys are afraid of the monster that supposedly lurks beyond the roped-off staircase called the Hatch. Jonathan decides he wants to know what the Hatch is hiding, and his efforts to explore reveal that the secret isn’t terrible after all as the librarian tells him the truth. His curiosity plays a key role in his character development as he overcomes his fears in order to learn more about the island and himself in the process.