Growing up is a motif in the story. The crisis in this story causes the characters in it to grow up very quickly. Jonny begins the story as a child, but soon becomes very quiet and withdrawn. He does what he is told, but shows that he picks up on the feelings around him and asks questions about their future. He deals with events calmly and appears to perfectly understand the severity of what is happening. He shows very mature behavior on his birthday, and never throws tantrums or gets into fights. In some ways he acts more maturely than Miranda, though this is partly because he is more sheltered from the worry than she is.