Sister Andrea joins the team to fix a demonically possessed marriage, and Leland and Sheryl continue their crusade for Satan.

Morland offers to act as one of his son’s “Irregular” consultants so that he can lend Sherlock and Joan his considerable resources to help them solve a case.

The District Attorney’s Office is set on its ear when the investigation into the death of an A.D.A. uncovers a scandal that could imperil hundreds of cases.

The death of a lab technician and the abduction of 17 infected monkeys lead to a trial involving the treatment of research animals.

The investigation into how a teen got wounded leads to a case involving a young woman’s murder and a drug operation.