Despite having a good time teaching Eve how to drive, Mike thinks Vanessa should take over so she and Eve can bond; Mandy is annoyed by Mike's endless requests for Kyle to do work around the house.
Sherlock must face his past when he travels to London to revisit an old case; Watson learns more about Sherlock's pre-New York life; Sherlock's brother, Mycroft, reveals some secrets.
In the Season 12 premiere, Peter believes a restaurant place mat to be a treasure map, and soon the residents of Quahog are turning the town upside down and turning against each other.
The Jeffersonian team investigates the murder of Jamie Delcampo, a member of the Estrellas Locas gang, whose remains were found in a burnt out car. Meanwhile, having taken time off from the FBI in the wake of Pelant's latest assault on the team, Sweets ultimately decides to help with the investigation when he discovers that a young boy from the center where he volunteers is the son of one of the gang members.
Beckett races to find a stolen toxin capable of killing thousands of people; Castle has less than 24 hours to live after being exposed to the chemical weapon.
Duncan informs Ellen that her refusal to assassinate the president will cost her a loved one's life; the family learns it will be monitored by Duncan's men until the operation.
When Kate asks Pete for more responsibility, he entrusts her to put Bert to bed and help him coach Bert's soccer team. Before soccer practice, Bert drinks Kate's coffee and becomes a wild man on the field before crashing. Meanwhile, Warren and Hillary spill salsa on Diane's immaculate white couch and try to hide it from her.
After returning from Haiti, Casey has an identity crisis and thinks being a disc jockey might be his new calling. When Mindy and the office go to a music festival for their "work retreat" to see Casey perform, the substance-filled surroundings lead to a series of disasters. Meanwhile, back in New York, Jeremy hires a new doctor, whom Mindy doesn't particularly like after he saves the day during an emergency delivery.
In an effort to help Sam and Deeks return to work, Hetty calls upon Operational Psychologist Nate Getz to help them cope with their traumatic experience. Meanwhile, the rest of the NCIS: LA team investigates the murder of a former Navy Admiral and a controversial journalist aboard a private jet.
Thinking Schmidt has chosen to be with Cece, Jess and Nick invite him to go on a double date with them. Nick is caught between loyalty to his friend and loyalty to his girlfriend when he finds out a shocking secret. Meanwhile, Winston promises to get the foursome a table at an ultra-exclusive restaurant that doesn't take reservations.