Great question! In the book The Adventures of Tom Sawyer by Mark Twain, Mrs. Thatcher and Aunt Polly become worried.
After the picnic, Mrs. Thatcher and Aunt Polly go to church. Mrs. Thatcher and Aunt Polly believe that Becky and Tom stayed the night at the Harper’s household. However, Mrs. Harper quickly informs them that they did not spend the night with her family. Consequently, they soon become worried. As the text reveals:
“‘He didn’t stay with us,’ said Mrs. Harper, beginning to look uneasy. A marked anxiety came into Aunt Polly’s face.”
Subsequently, Mrs. Harper and Aunt Polly become exceedingly worried and anxious due to their fears of Tom and Becky being lost in a cave. Although the town is looking for the children, Mrs. Harper and Aunt Polly continue in their feelings. Furthermore, despite encouragement and comfort, these feelings fail to be ameliorated. As the text reveals:
"Many women visited Aunt Polly and Mrs. Thatcher and tried to comfort them."
"Judge Thatcher sent messages of hope and encouragement from the cave, but they conveyed no real cheer."
Thus, Mrs. Thatcher and Aunt Polly become worried after they realize that Becky and Tom are missing. Although they initially believe that the children are staying at the Harper’s, they soon realize their misconceptions. Consequently, their worries begin.