After years of protecting New York from ghosts, the Ghostbusters have retired and settled down. Now it's their children's turn to save the world from paranormal ghouls. Oscar, Jordan, Isaac, and Audrey must defeat and capture the ghosts haunting New York. But will a greater evil power defeat the Ghostbusters?

While patrolling the city of New York, Leo and Raph come across a girl who may or may not have been tested or involved with the Kraang. After bringing her back to the lair, she befriends the turtles and the TMNT think that they have found themselves a new addition to the team, but the mystery of their newcomer's past with the Kraang still hangs in the background.

After almost being captured by the Kraang, Julie is saved by the Teenage Mutant Ninja Turtles. But when all seems well, Julie starts to have weird dreams and senses. Donatello suspects that Julie knows what the Kraang are planning through visions and nightmares, and thinks that Julie was infected by mutagine. Will Julie be able to stand this change?