When Katie brings her maybe-someday stepsister to Cupcake Club, she gets her first taste of sibling rivalryand its not very sweet!

Katies mom asks Katie for a huge favor: will she spend some time with Emily, her boyfriends daughter? Katie agrees and brings Emily to a Cupcake Club meeting. Things go wellalmosttoowell. Everyone likes Emily so much, Katie wonders if her friends like Emily more than they like her! And if her mom marries Emilys dad, will Emily become her favorite daughter? Katie is an only child, so all this sibling stuff is new to her. Shes starting from scratch!