Janie Tam is the protagonist’s older sister. Like many siblings, Bat and Janie have contrasting personalities, interests, and communication styles. While Bat is reserved and dislikes attention, the creative, outgoing girl declares that she “was born for the spotlight” and channels her love of singing and acting into her school’s production of Alice in Wonderland (70). When Bat observes his sister enjoying time with her castmates seemingly effortlessly, he describes her as “a social butterfly” (130), and this observation makes him more painfully conscious of his own difficulties connecting with his peers. Despite their many differences, Bat becomes more aware of their similarities when they reconcile at the end of the novel: “[H]e stared right into Janie’s eyes, which were almost exactly like his own eyes, Bat realized, a brown so dark it was almost black, and shiny” (169). The siblings’ family resemblance underscores that they have a great deal in common and will always share a special bond, even though they have their share of disagreements, as siblings are wont to do.

Janie facilitates the novel’s plot and thematic exploration of empathy and The Challenges of Navigating Shifting Family Relationships. Her involvement in the school play shapes the story’s structure and forces Bat to make changes to his routine that are initially discomfiting but ultimately increase his appreciation for Janie and Israel. Thor’s first spray at the opening night of Janie’s play marks a turning point in the story and escalates the tension between the siblings: “Janie and Bat didn’t always get along. [….] But this felt different. This felt huge” (157). Bat’s realization that his choices hurt his sister advances his developing compassion, and the siblings’ reconciliation gives the novel its happy ending.

Dr. Valerie Tam is Bat and Janie’s mother. Although Arnold’s prose doesn’t offer a description of the woman’s features, it provides detailed tactile and olfactory imagery about her: “Bat closed his eyes as he let his face mush into the softness of her stomach. He felt the snug tightness of her arms around his shoulders and back, the gentle, firm pressure of her embrace. […] Mom smelled of rosemary, like sunshine and peppermint and pine” (23). This imagery illustrates how Dr. Tam’s presence represents comfort and safety for her son. Her calm, caring, and intelligent personality aligns with her profession as a veterinarian, and she nurtures Bat’s love of animals, which is an integral part of his character. Importantly, Arnold shows her making missteps, such as when she “pushed Bat over the edge” by calling him “Baby” when he’s feeling distressed (64). This scene demonstrates that parents are human and, therefore, bound to make mistakes. The novel argues that providing consistent care and effort is more important than aiming for perfection.

Dr. Tam’s parenting style emphasizes the novel’s themes of supportive environments and developing empathy and patience. She consistently models these values in her interactions with her son and encourages him to extend them to others, especially Janie. For example, she helps her children see that each other’s perspectives about theatre are both valid: “‘There’s room in a theater for the performers and the audience,’ Mom said. ‘A show isn’t a show without both’” (71). Arnold demonstrates Dr. Tam’s attentiveness to her son’s physical and emotional needs through details like their waiting games and the nonverbal signals she and Bat use to communicate whether he wants physical affection or assistance. Dr. Tam’s understanding and steadfast support of Bat is a major factor in the novel’s affirming treatment of neurodivergence.

Mr. Tam is Bat and Janie’s father and Dr. Tam’s ex-husband. Arnold portrays him as detail-oriented and organized through his profession as a computer engineer and his love of statistics. He has a fastidious side, as indicated by his refusal to allow animals in his apartment. Throughout the story, Mr. Tam insists on calling his son the nickname “sport” despite the protagonist’s disinterest in athletics and his preference for being called Bat. This detail alludes to the broader pattern of Mr. Tam expecting Bat to conform to his neurotypical expectations about how his son should behave rather than adapting his own behavior to better support Bat’s needs, the way Dr. Tam does. Most of Mr. Tam’s development occurs during the baseball game in Chapters 12 and 13, which highlights both his love for his son and his inattention towards his needs. Although the baseball game is so far outside of Bat’s comfort zone that the experience makes him question “if his dad really [understands] him” (78), Mr. Tam shows his desire to connect with Bat when he explains that his favorite thing about the sport is “[s]itting next to someone [he] love[s]” (87). The author characterizes Mr. Tam as a flawed but well-intentioned parent.

Mr. Tam acts as a foil to Dr. Tam, broadening the novel’s exploration of parenting styles, empathy, and familial relationships. Although he doesn’t adapt to Bat’s needs and comfort zone the way his ex-wife does, Mr. Tam begins to develop a closer bond with his son after their experience at the baseball game. He advances the theme of empathy by challenging Bat “to appreciate other people’s interests” (84), a lesson Bat later applies at his sister’s play. Dr. Tam and Mr. Tam’s divorce emphasizes the challenges of navigating shifting family relationships as a central theme in the novel. Although they’ve been divorced for about a year and a half when the story begins, the family members are still adjusting to their new dynamics. Part of why Bat struggles with the divorce is that his father doesn’t appear to make much effort to understand his emotional and sensory needs, which makes his weekends at Mr. Tam’s apartment challenging for him. On the other hand, Arnold includes Mr. Tam in Janie’s performance at the story’s happy ending, which indicates his commitment to remaining actively involved in his children’s lives and contributing to their supportive environment.