After Porsche and Lockie’s wedding, the McQueens, minus Nana, who has taken the kids home, all board the party train.

Meanwhile, Patrick leaves Maxine alone to go to school but has downloaded a spy app on her phone. Dodger turns up at the McQueen wedding to play happy families with Theresa and leaves one last message for Maxine in the hope she still loves him.

Fortunately for him, she does, and when she decides she can’t be apart from him any longer, she puts her faith in a bitter Sienna, who reluctantly drives Maxine to the train station to find him. Little do they know, Patrick is tracking their every move…

Back on the party train, everyone’s in high spirits. But they’re oblivious to the danger ahead.