Bela goes to Chaps Park with Mommy and her friend Deb, while Daddo stays home working. As Mommy talks intensely with Deb's mother, Carly, Bela and Deb swing and discuss a new school weapons check. Bela keeps thinking about Mommy's recent secrecy, Mommy's warning about living in fear, and the woman who lives in Bela's closet.

Bela then turns the conversation into a test. Bela asks Deb what Deb would do if a bad woman lived in Bela's closet, watched Bela from the bathroom, or lay beside Bela in bed. Deb first says Deb would tell Bela's parents and even imagines fighting the woman, but as Bela keeps pressing for answers, Deb becomes frightened and tries to end the conversation.

Deb runs to the jungle gym, and Bela follows, still asking whether Deb would tell an adult even if the adult might get hurt. While Deb hides in one of the wooden play spaces, Bela recognizes that Bela is being mean. Bela remembers Daddo's lessons about kindness, cruelty, and refusing to let someone else's meanness inside, which gives Bela a moral frame for what is happening.

When Bela climbs up to apologize, Deb is crying in the dark. Then the voice in the wooden room asks, "Can I go into your heart?" Bela looks down and sees the real Deb already running back toward the adults, which means something else is inside the jungle gym. Bela sees hairy fingers curling around the entrance, realizes Other Mommy is there, screams for Mommy, and falls backward down the slide.

After the fall, Mommy and Carly rush over, and Bela sees Deb frightened in Carly's arms. Mommy now smells like herself again as she asks what happened, but Bela can barely answer except to say Bela is terrified. Looking back toward the wooden room, Bela understands the chapter's major escalation: for the first time, Other Mommy is outside the house.