-Megan comes back to work after three months leave due to Peter's death. 

-Bud and Sam have both left the force. Detective Tommy Sullivan, an old flame of Megan's joins the Philadelphia P.D. 

-Five combat veterans are found dead. Each had their spleens removed, were stabbed, and then had their throats slit all 48 apart. Megan tracks the specialty sutures to a plastic surgeon, Dr. Wallace but there isn't enough evidence to arrest him.

-Another veteran, Carl Simmons is abducted while Tommy and his partner Det. Adam Lucas are watching him. Curtis finds a strange beetle on the bodies and it leads them to the quarantine area at the Port of Philadelphia. 

-Tommy shoots and kills Dr. Wallace as he holds a gun on Det. Lucas. Before Tommy dies he says "they made me do it." Megan saves Carl who is unconscious and bleeding on a surgical table while another victim lies dead next to him.

-Ethan's find of surgical mesh and the makeshift surgery room makes Megan believe that Dr. Wallace didn't do this alone but Kate goes ahead with her press conference. She likes the good publicity, especially since she plans to run for public office.

-While Megan finds an electronic device surgically implanted in the last victim. Before she can figure out what it is her phone rings. An electronically modified voice tells her that they have Lacey and she needs to do exactly what they say.

-We see Dr. Wallace's nurse, Yvonne holding an unconscious Lacey hostage.