The Cupcake Club comes to Katie’s defense when a surprise at school leads to unfair gossip. When Katie’s mom says it’s time for Katie to meet her new boyfriend, Katie is excited and nervous. She thinks she’s prepared, but she’s shocked instead. Her mom’s boyfriend is Jeff Green—as in Mr. Green, a math teacher in her grade! Katie tries to act as normal as possible, but when mean girl Olivia finds out, she tells everyone that Katie is getting special treatment because her mom is dating a teacher. How can Katie stop Olivia and deal with all the new events in her life? It’s the Cupcake Club to the rescue, as Katie’s friends come to her defense, including an unexpected ally.

Katie is about to burst when the rest of the Cupcake Club entrusts her with their secrets, but this group of best friends soon realizes that sharing and keeping secrets is what friends are for.

Mia goes on vacation and meets up with the girls from the Sprinkle Sundays series in the latest addition to the Cupcake Diaries series! Things are slow at the cupcake shop this summer, and so when Mia’s dad invites her on a long weekend trip to meet some of his college friends, she jumps at the chance—especially when she hears they have daughters her age. It turns out the girls work in an ice cream shop. Not only does Mia end up making new friends—she comes back with a new invention for the Cupcake Girls: an ice-cream cone cupcake!

The girls realize that it is great to have friends and they are a lot like cupcakes you can't have enough and they are good in all combinations.

Can the new Fashion Club be the icing on the cupcake for Mia, or is she in over her headshot? When fashionista Mia hears someone is starting a Fashion Club at school, how can she resist? But can she manage to take part in two clubs at the same time? And what will her Cupcake Club friends think about this? Worst of all, Mia’s frenemy Olivia Allen wants to be in charge of the Fashion Club. Can Mia and Olivia make peace long enough to survive a fashion show?

When Katie brings her maybe-someday stepsister to Cupcake Club, she gets her first taste of sibling rivalry—and it’s not very sweet! Katie’s mom asks Katie for a huge favor: will she spend some time with Emily, her boyfriend’s daughter? Katie agrees and brings Emily to a Cupcake Club meeting. Things go well—almost too well. Everyone likes Emily so much, Katie wonders if her friends like Emily more than they like her! And if her mom marries Emily’s dad, will Emily become her favorite daughter? Katie is an only child, so all this sibling stuff is new to her. She’s starting from scratch!