This story discusses the arrival of a new child in the family and exposes Sara's feelings. Sara is a child just like any other happy child: she is talkative, curious, and restless. She is always looking for new adventures and meeting interesting people. The newcomer is a new book in the series after The girl who liked to Know everything, Sara's family, Sara's hair, The saci in the garden, There is a ghost in my house, The little champion, Sara Goes to Japan and Sara goes to the Beach.