Seamus Callahan is Anna’s friend and co-conspirator on her plan to exact justice upon those responsible for the 1942 explosion. Seamus’s older brother, Sean, was one of the soldiers aboard the train who died, and Seamus was one of the only ones to reply to Retta’s letters insisting that Arthur was innocent. Retta gave the evidence to Seamus before her death. Seamus attended Retta’s funeral, during which he met Anna and provided her the evidence necessary to exonerate her father. Anna and Seamus grew close because of their shared pain, as Anna thinks that “theirs is an unusual bond, forged through unimaginable grief and the strangest of circumstances” (184). Their friendship is close because they understand each other, but their romantic relationship never blossomed. Seamus loves Anna, but Anna found their singular intimate encounter too sad to continue on. Seamus understands, but his love for Anna does not stop him from breaking apart their initial plan to seek justice.

Seamus has a degenerative condition that gives him muscle spasms that his doctor says is terminal. He does not have time to wait for the justice system to mete out punishment for those who killed his brother, as he may not be alive to see them suffer the way he wants to. He kills Judd himself and attempts to kill Jack before Anna catches him. Anna’s reaction harkens back to their initial meeting, in which “she vividly remembers Seamus’s words after they first sorted through those boxes of proof. All of them need to die. And I want to be the one to do it. And so he had” (408). Seamus wanted his personal revenge, so he worked to obtain it behind Anna’s back. After she discovers his secret plan, he jumps off the Philadelphia Phoenix to avoid both going to prison for murder and suffering a drawn-out death as a result of his medical condition.

Seamus embodies both loyalty and self-destruction. His friendship with Anna is rooted in shared loss, but his illness and impatience with justice twist his devotion into ruthless vengeance. His decision to kill Judd and betray their plan reflects not only his anger but also his despair at his own mortality, showing a man who cannot bear to let time rob him of retribution. Seamus is a tragic figure, sympathetic yet compromised, who illustrates how grief can harden into obsession. His final leap from the train mirrors his inability to reconcile loyalty and revenge, casting him as both ally and cautionary tale in Anna’s quest.

Reginald, or Reggie, Davis is an antagonist in the text. He works as an FBI agent, and he is tasked with observing Anna and Seamus’s plan aboard the Philadelphia Phoenix while posing as an insurance salesman who simply boarded the wrong train. This assignment offers Reggie the perfect opportunity to seek his own revenge. Reggie was 15 in 1942 when the train exploded, and his father was the engineer driving the locomotive. His father was killed, and Reggie joined the FBI to ensure that no one else suffered the same way he did. However, boarding the Phoenix offers Reggie the opportunity to see his own revenge on the conspirators that contributed to his father’s death. He uses the investigative skills he cultivated at the FBI to realize Judd faked his death, and he convinces Judd to help him begin picking off the other conspirators. Reggie pretends to investigate his own killings, illustrating his ability to manipulate those around him. He builds trust with Anna through manipulation, but he serves as a foil for her. Anna herself has investigative abilities and can eventually see through his charade. Though they both lost family members, Anna still adheres to the ideals of justice while Reggie seeks revenge.

However, Reggie is not an irredeemable character. At the end of the novel, he tells Anna that he took the fall for killing Judd to allow Seamus’s reputation to remain unblemished. He tells Anna, “Try to forget. And try to forgive him. Hopefully me taking the fall for it will help with that. Seeing how I’m about to be locked up for God knows how long, it’s the least I can do” (472). Reggie seeks revenge against the people who hurt his family, but he does not want to hurt anyone else unless they seek to block his plan. He is a complex character, mired in the gray areas of revenge and morality as he seeks to recover from his own painful past.

Reggie represents the most complex face of vengeance in the novel. His FBI training gives him discipline, but his grief over his father’s death drives him into manipulation and violence, making him both investigator and criminal. Unlike Seamus, who burns openly with rage, Reggie conceals his motives behind charm and calculation, forcing Anna to grapple with the blurred line between justice and vengeance. Yet his decision to protect Seamus’s reputation and offer Anna moments of companionship hints at an inner conflict: He is capable of care even as he wounds. Reggie symbolizes the moral ambiguity at the heart of the novel, where survival and revenge are deeply human impulses that cannot always be cleanly separated from love or loyalty.

Dante Wentworth is Anna’s former romantic interest and the son of Kenneth. He is described as “young, handsome, charming, and rich” (56). However, despite his affluence, he struggles emotionally. His father neglected him throughout his childhood, and Dante could never win his affection. His father also forced Dante to break up with Anna during their romantic relationship, which broke Anna’s heart and also hurt Dante badly. Kenneth never told Dante about his plot, but he did not want Dante’s relationship with Anna to interrupt his plans. Kenneth also knew that Tommy Matheson was his biological son, and he sought to keep distance between Dante and the Mathesons because of his anger.

The relationship between Dante and Anna in 1954 is fractured because of the heartache of the past. Anna doesn’t know or trust Dante like she once did, so she cannot know his intentions. When the group attempts to force their way into the locomotive to stop the train, Anna wonders if Dante as a Wentworth will use his influence to force the engineer to stop. She notes, “Dante turns to give Anna a look she finds unreadable. For a second, she can’t breathe, certain he’s about to single-handedly stop the train and ruin her plan…All that plotting for nothing. All that expense wasted. But then that crooked grin spreads across his face, and Anna exhales” (123). Though Anna is at first uncertain of Dante’s aims, as soon as he smiles she realizes that he’s on her side. Though the 12 years and heartache have eroded some of the intimacy between Dante and Anna, they still share a bond. Dante’s role in delivering the evidence to Retta illustrates his allegiance to the truth and to Anna, though they end the novel deciding to remain just friends, as their shared brother prohibits a romantic relationship.

Dante embodies the novel’s discussion of fractured inheritance. As Kenneth’s son, he carries the burden of a name stained by betrayal, yet he rejects his father’s cruelty to align himself with Anna and the truth. His relationship with Anna, though once romantic, becomes a testament to the endurance of trust across grief and time. Dante is not as actively vengeful as Anna, Seamus, or Reggie, but his quiet defiance of Kenneth reveals a gentler form of resistance. He is caught between two legacies—his father’s corruption and Anna’s pursuit of justice—and his choice to support Anna without rekindling romance suggests maturity born from pain. Dante symbolizes the possibility of breaking from destructive lineage while still carrying its scars.