Missing scene from What You Can't See where Ethan has to find a way to get a sample of Danny's blood. He's torn between deception and burgeoning real affection.

Some time after returning from Mexico, Derek awakes from a nightmare about Kate. Stiles helps him through the PTSD episode with simple gestures and quiet understanding.

Starts where 3B stops, with Kate attacking Derek in the loft. She kidnaps him to Mexico, and Stiles, Scott, and Lydia rush to find him before Kate can inflict too much damage. She inflicts enough, and Derek retreats into his mind to escape the horrors of his situation. The Derek they find is not the one that left Beacon Hills.

After the nogitsune is taken care of, Chris disappears into his mourning for Allison. No one has seen or heard from him, and Derek decides to not leave him alone in his grief.

Derek wakes up from the fly-possession and deals with the fallout.

Missing scene from the end of 3x19 where Chris removes the glass from Derek's back.

A new threat comes to Beacon Hills, putting all its supernatural inhabitants in danger. A true alpha and banshee are rare and valuable quarry, but Stiles and Derek are the easiest targets.