Final answer:
Atticus Finch tells his children that Boo Radley wrapped a blanket around Scout during Miss Maudie's house fire. This act surprises and upsets them, leading them to reconsider their views on Boo.
Step-by-step explanation:
In the novel To Kill a Mockingbird by Harper Lee, Atticus Finch upsets his children, Jem and Scout, by revealing to them that Boo Radley wrapped a blanket around Scout without her noticing. This event occurs when Miss Maudie's house catches fire, and everyone in the neighborhood comes out to see what is happening. While Scout is engrossed in watching the blaze, Boo Radley comes out of his house and places the blanket around her in a protective and caring gesture without her awareness.
This revelation surprises Scout and Jem because of the mysterious nature surrounding their neighbor, Boo Radley. Despite their initial fear of Boo, this act of kindness helps the Finch children begin to understand and reevaluate their perceptions of him. This moment is significant because it represents a turning point in Scout and Jem's understanding of the complexity and goodness that can lie within people who are perceived as 'different' or 'scary'.