Keep calm and call the midwife . . . Maeve O'Reilly Kensington is still shaking off last year's shocking events in the quiet New England coastal town of Langford, where she is a modern-day nurse midwife. Her husband Will's catering company, A Thyme for All Seasons, is back on an even keel, and they are now actively pursuing fertility treatment and adoption in the hopes of becoming parents.

Meg, Maeve's older sister and Langford's premier real estate agent, introduces her to Montgomery Livingstone, a Manhattan business tycoon commonly known as the Takeover King. Livingstone is anxious to move his base of operations and his home to Langford, but some community members have grave misgivings about whether his presence will be a boon for the town.

Misgivings that come to fruition when Monty is pushed off a Widow's Walk and falls to his death! Suddenly Maeve and Meg are again thrust into a murder investigation as they attempt to help a seemingly innocent young woman accused of the crime. But it turns out there are many secrets to be uncovered, and once again, Maeve, Meg, and their savvy Boston Irish mother must band together to solve the murder. Maeve races against the clock to bring the killer to justice while caring for her patients and pursuing her goal of motherhood.