Isa is a sensitive, talented musician and, along with her twin sister Jessie, is the oldest of the Vanderbeeker children. Though she shares the top spot with her twin, Isa embodies the typical older child who is dutiful, responsible and takes charge of her younger siblings. When she’s not with her other siblings, Isa can be found in the basement of their brownstone practicing her violin. Isa has transformed what Jessie calls a dungeon into a soundproof studio where she can practice all the skills that she learns from her beloved violin teacher Mr. Van Hooten. As soon as Papa announces that the Beiderman will not renew their lease, Isa worries that she and her violin music are the cause. Throughout the narrative, Isa leads her siblings with quiet strength, but internally she struggles with self-doubt and a fear of failure. She draws from Jessie’s bold, rational strength while keeping her anxieties secret and she says, “See Jessie, you make me strong. Sometimes I think you know every thought that goes through my head” (161). When the children move to action, it is Isa who pushes them to extend friendship and kindness to the Beiderman instead of seeking vengeance.