Nicholas' single dad has very bad cancer and he's going to die, soon. So Nicholas offers himself up to be the guardian for his two teenage half-sisters. What's the worst that can happen?

Nicholas wishes he could call an adult. After the death of their father, Nicholas, Matilda, and Genevieve struggle to return to their daily - and nightly - routines.

Nicholas is terrible at love; Genevieve's ambivalence about Nicholas' boyfriend Alex takes an unfortunate turn when the three go out together; Matilda wants to bake Luke a cake but takes her brother's advice.

Alex throws a dinner party for his friends to meet Nicholas who has to keep a secret. Matilda makes out with a boy at a party who tells her to keep it secret. Gen is upset about what Matilda tells her.

Nicholas is called to the principal's office. He and his boyfriend later go to Mexico for vacation, but have a big argument.

Matilda brings a friend home to support her as she awaits some news. Gen and her friends devise a plot to help Barb. Nicholas' mom video chats with Nicholas, Alex and his sisters and their friends.

Alex puts Nicholas in the naughty corner. Nicholas and Alex work through their relationship issues at home. Matilda and Genevieve find themselves confronting sexuality at school in very different ways. Genevieve is forced to grow up.

Matilda focuses on her relationship. Nicholas faces a reality check at Matilda and Genevieve's parent/teacher conference. He figures out how to get them to wake up and try.

Nicholas, Matilda and Genevieve go to New York to practice traveling with the underground. Matilda wants to do the same track over and over while Genevieve goes out one night on her own.