On Teen Wolf Season 6 Episode 15, Theo finds himself being tortured next to two other werewolves. After they manage to get free, Theo tells them that they should go find Scott McCall. As the three of them leave the warehouse, Sheriff Stilinski shows up and arrests them all for murder.
In the jail cell, Theo learns that the other two wolves killed hunters in self defense. This earns him his freedom; however the other two wolves are still being held. Scott and company try to get Sheriff Stilinski to release the two wolves, and they tell him about one of his deputies working with the hunters.
Speaking of Monroe and her hunters, they surround the Sheriff's station. They give Sheriff Stilinski until midnight to release the two wolves he has in his jail cell. Monroe isn't about to wait patiently though.
She sends Nolan in, and even though he knows the two wolves, he still tries to kill them. Luckily, Liam is there to stop Nolan. Unfortunately for everyone, the faceless corpse aka the body from the rift is in the station as well, and its inciting fear.
Meanwhile, Deaton makes a visit to Eichen House. He goes into a cell that reeks of fear and retrieves what appears to be a piece of the wall with a carving of a face on it.
Corey and Mason try to research what came out of the rift, and they think they should start with the wolves - the first creatures that showed sign of immense fear. They break into Deaton's clinic, and Deaton shares what he found at Eichen with them.
Corey can see the other half of the carving. It's actually a carving of two faces, not one, that are connected. Deaton explains that he knows what is causing the fear -- an ancient shapeshifter that feeds off fear.
Back at the Sheriff's station, Scott tries to fool Monroe by delivering corpses of two deputies who fell victim to the faceless corpse's fear. Scott believes that Monroe has never seen the two wolves, so he thinks she will buy it.
Then, Scott's dad shows up to broker a deal. It turns out Sheriff Stilinski called for back up right when everything started, but he never thought anyone, let alone Scott's dad, would actually show up.
Scott agrees to the deal. The terms are that the two wolves get handed over to the FBI, and Scott and the rest of the supernaturals leave California. Monroe had an inside man with the feds, so after the two wolves are driven away, they are killed.
Scott and the pack lie to everyone when they say they are leaving Beacon Hills. In actuality, they are staying. It's time to fight.