The Baby-Sitters Club: Mary Anne Saves the Day Book 4 by Ann M. Martin

Mary Anne has never been a leader of the BSC. So when a fight breaks out among the club's four members, Mary Anne feels a little lost, unable to depend on Kristy, Stacey, or Claudia anymore.Sitting by herself in the cafeteria is bad enough; when Mary Anne has to baby-sit a sick child without any help from the club, she knows someone has to take action. It's time for Mary Anne to step in and save the day!