Just one week after Peter Bishop saved the day and was then wiped from existence, the truce between the two worlds remains intact and the two sides are forced to work together. Lincoln Lee joins the Fringe team as they investigate a shapeshifter case that is very personal to him.
As the victims of a highly intelligent serial killer “Over There” stack up, the Fringe Division “Over Here” is asked to assist. As the two sides tangle and innocent people remain at risk, the suspect’s doppelganger “Over Here,” a professor who teaches Forensic Psychology, is brought into the fold and forces the team to consider the notion of sending civilians to the other side.
When two 12-year-old kids bully another boy, they are found dead and in just hours after dying, their bodies are shockingly in an advanced state of decomposition. As the Fringe team investigates the mysterious case, they uncover an amorphous figure claiming more victims. Meanwhile, Walter becomes increasingly distracted by his hallucinations.
Walter is wary of leaving the sanctuary of his lab for the first time in years when he and Olivia go to Massive Dynamic in New York to study old files after she discovers a powerful force that may be linked to his Cortexiphan experiments.
The threatening return of the translucent shape-shifters coincides with the reemergence of a former Massive Dynamic scientist (Arye Gross). Meanwhile, Walter gets a visit in the lab from Nina Sharp.