A year after the Ghostbusters defeated Vigo the Carpathian, a ghost named Poso kidnaps Janine and Louis to force the Ghostbusters to hand over their business. The Ghostbusters get help from a recently-captured ghost, Shifter, to find out why Poso wants their business and where to find him. Covered in mood slime, Peter goes to the Ghost Town to save Louis and Janine.