Dr Turner and Nurse Crane must deal with an alarming outbreak of diphtheria. Fred finds an abandoned baby in a dustbin, and the team must help locate its mother.

A terrifying plan to destroy humanity is about to reach fruition. Can the Doctor and her friends escape multiple traps and defeat a deadly alliance?

Lois gets a job teaching music at Chris and Meg's school after learning the students were being taught by a bird. Connie D'Amico decides to bully Lois who in turn threatens Connie publicly. When Connie is apparently murdered, Lois Griffin gets thrown into prison.

CIA Officer Veronica Stephens asks the NCIS team for help when an agricultural engineer Hetty asked her to bring to the United States disappears.

Gary O’Malley seeks justice from the Sullivans, while Ray and Smitty must cover for their own actions. Daryll calls Jasmine with an opportunity that lands them face-to-face with Declan Sullivan. Terry and Bunchy head back upstate to settle some unfinished business with the Shaman.

Frank goes back in time to uncover his connection to Faye, as Debbie’s day with Claudia’s daughter goes awry. Carl takes extreme measures to toughen up his new group of cadets. Ian struggles to connect with Mickey after their blowup.

Homer and Marge attend Artie Ziff’s wedding and become quite uncomfortable when they realize that his bride-to-be is a clone of Marge. Meanwhile, Lisa grapples with the misogynistic implications of the immediate popularity she receives after getting her new Invisalign braces.