When a young boy is taken over by a malevolent spirit, John must put aside his misgivings over exorcising a child and convince the parents that their boy is not all that he seems.
Cory and Topanga are going out to celebrate their anniversary and decide to let Riley babysit Auggie for the first time. She enlists Maya's help, which leads Auggie to rebel against the girls.
The justification for Nick to become a Grimm again is made much clearer in the wake of the most recent attack against Monroe and Rosalee. At work, Nick and Hank are called to a stretch of highway that acts as a staging area for a horrifying Wesen ritual. In Vienna, Viktor meets with a completely broken Adalind, now ready to be of assistance in finding and retrieving the baby. Meanwhile, Trubel is surprised by the sudden arrival of an old friend.
When a trouble drives Haven’s citizens to pursue their more primal desires, it takes everyone to keep Haven from coming unglued-distracting them from the menacing storm that is brewing.
Murphy is kidnapped by a group of outlaws trying to crack the "Fort Knox of Oxycontin." As the survivors battle drug-enhanced zombies, a startling discovery is made about Murphy's abilities.