Jamal, Lenni, and Alex are graduating from middle school and Tina is hosting the party, while Jamal and Tina work on the prom committee. However, the band that was supposed to play at the prom backed out. Jamal and Tina convince Lenni to play with Tina's brother Tuan. However, Lenni and Tuan get off to a bad start. Eventually, they learn to play their music together. In the meantime, Alex has been writing the story. He writes about the Slime Monster running away and kidnapping Gaby and about his attempts to save her.
Casey is writing a scary story for a local contest about ""Gooey Gus: the Slime Monster"", a doll that spits out grape bubblegum. Casey thinks her story isn't scary enough, so she asks for Lenni's help. Lenni adds atmosphere and writes how the Slime Monster is about to come after Casey. Alex and Gaby come to help, too, and Gaby writes about Alex and Jamal finding the Slime Monster seemingly alive in an alley, and then Alex, Gaby, and Casey find the Slime Monster in a crock pot.
Gaby is taken to the smugglers hide their she encounters two wanted criminals Adoment Poulet and Honey Hawke who have been smuggling endangered birds into the country and skinning them alive. Gaby leaves a message for the team but before she can finish she is captured and put in a giant bird cage. The team learns of Gaby's whereabouts and meet up with the real agents from the animal rights society. They discover where Gaby is and heads straight for the kidnappers lair. Poulet and Hawke are captured and Gaby gives the bird to the agents so they can help restore its species.
Hector and Lenni are able to warn Alex and Gaby about the smugglers the retreat back to Lenni's apartment. Jamal and Tina learn that Palm Cockatoos are endangered species,so the team tries to contact the police but it doesn't work so they contact the fish and wild life service, an animal rights society. They tell Mr. Fernandez that they won't give the bird to anyone except the fish and wild life people. Hawke, disguised as a pregnant woman overhears them and has a new idea. Just then two agents from the wild life society arrive at the bodega but Gaby reads a message from Ghostwriter and realizes that they are imposters, but when she goes to save Calypso the van takes off with her inside.
Gaby finds a name tag on the bird and learns that its a palm cockatoo, and they nickname the bird Calypso. Casey still can't understand why she can't go home to her mother. Gaby decides to make some flyers for Calypso's real owner. Hawke finds one of them and makes a phony call pretending to be the bird's real owner. Just then Calvin arrives at Lenni's house and informs the team that palm cockatoos aren't permitted in the usa. The team realizes that Gaby is giving the bird to a smuggler,so they leave hoping to warn Gaby before it's too late.