Jessie finds herself in unfamiliar territory when Emma's unexpected behavior gets her into trouble at school. Meanwhile, Luke takes on the role of Sensei to train Zuri for her upcoming karate belt test.
When the kids are snowed in at the penthouse, an epic game of capture the flag ensues. Allegiances are tested, tricks are pulled and everyone goes a little overboard.
Jessie entrusts her favorite toy from her childhood, Military Mary, to Zuri, but when Zuri trades it for a far less impressive toy, they try desperately to get Military Mary back.
Luke becomes curious about the identities of his biological parents, and starts to investigate with Emma's help after Jessie refuses. However, things don't turn out the way he expected. Meanwhile, Ravi runs for reptile club president.
When Jessie makes the Ross kids bring Stuart along for trick-or-treat he tells them a haunting story about Abigail, a ghost who is out to get them. One by one, the kids mysteriously disappear.
Jessie's stepsister Darla comes to visit, and Jessie enlists Tony's help to try to cover up the fact she didn't go through with the wedding. Meanwhile, Luke shaves for the first time and when Bertram comes to help, things get a bit hairy.
In the series finale, when Christina Ross returns home, Jessie heads to L.A. for a role in a movie. But when the kids realize that they still need her, they follow Jessie to Hollywood.
Connie returns, this time with her boarding school roommate Mackenzie, who appears even crazier than her. When she obsesses over Luke, Connie surprisingly defends him. But things may not be as they seem. Meanwhile, Emma gets fired from her job.