The film begins when Leah and Katie Mealey say "hello" to the kids and tell them it is comic book day and the best comic one is "The Perils of Lady Nova" when she gets captured by a wicked giant named Pete the Giant who always wants the teenage girl in perils and her rescuers are Go Gumballs Gumballs members Pip the Tin Man, Manu the One-Eye Martian, Fiona the Dancing Flower, Benny the Bigfoot and Tommy the Little Flying Cat, who come to rescue Lady Nova and fight the wicked giant. After that, Princess Winnie and her five-year-old daughter, Princess Robyn (Aubrey Anderson-Emmons), tell Katie and Leah that the Gabba gang's old friend, Jason Bateman, has come to visit everybody in Gabba Land.
Jason arrives to see DJ Lance, Muno, Foofa, Brobee, Toodee and Plex again along with DJ Junior and Nathan Davis. They tell him that it is comic book day and the best one is The Perils of Lady Nova. Jason tells the Gabba gang that Lady Nova and the Gumballs gang are coming to visit them for comic book day and they are so surprised to see them. Leah says to DJ Lance that she wants to meet Lady Nova and the gumballs and Robyn want to meet them too. DJ Lance tells the girls that they need to be patient and they understand that.