Jessie Prescott is an 18-year-old teenage girl who moves to New York to live on her own. Once she arrives, she incidentally accepts an offer to become the nanny of a high flying couple's four kids.
Jessie comes to the rescue when the condominium owner wants Ravi's pet lizard Mr. Kipling out of the building. Zuri brings home another imaginary friend and Luke and Emma work together in a school photo class project.
After Jessie accepts a date to go on lunch with Tony, Emma gives her dating advice from teen magazines. Ravi becomes the target of Luke's practical jokes.
Jessie teams up with Luke to beat the paintball rival who wins every year. Meanwhile, Zuri plans a tea party and Emma is invited and promptly uninvited by her best friends to Fashion Week.
Jessie wants Zuri to play with real friends instead of imaginary ones, but when Zuri befriends the much older Nana Bananas - who wears yellow track suits, talks to her late husband named Harold in the park, and constantly squeaks a yellow horn when she makes jokes, Jessie is worried. Meanwhile, Ravi thinks that Mr. Kipling has found true love with a playground dinosaur.
Jessie hires a new tutor for Luke but it turns out that the tutor has a huge crush on Luke. Meanwhile Ravi downloads an app that predicts the future and fears that Bertram will be endangered.
When Morgan and Christina get stuck in a snowstorm, the family fears they won't make it home in time for Christmas and Jessie is left with shopping for the kid's Christmas presents. When Jessie takes the kids to the mall to see Santa, they have a run-in with his mischievous elves.
Morgan asks A-list movie star teen heartthrob Jordan to stay with the Ross family so he can convince him to star in his next movie. Emma is clearly in love with him and jealousy flares when he asks Jessie out on a date.
Evil Nanny Agatha's beautiful, friendly sister visits, and has nowhere to sleep so Jessie invites her to stay. Heather isn't as nice as she seems and tries to steal Jessie's job.
Jessie plans Zuri's Gotcha Day: the day her adoptive parents brought her home. As the kids talk about adoption, Ravi learns that when Christina and Morgan got him, they were expecting him to be a baby.
