This is the story of how a new baby impacts a family, and is narrated by the family's imaginative 7-year-old son, Tim. The baby is a very unusual one. He arrives in a taxi, wearing a suit and carrying a briefcase. But Tim's instant case of sibling rivalry has to be put aside when he learns that the new addition is really a spy on a secret mission and he is the only one who can stop the evil plot that involves a full-scale battle between babies and puppies. Based on the picture book of the same name written by Marla Frazee.