Callie and Derek collaborate on a brain mapping project; Meredith thinks about continuing her mom's research; Shane's guilt persists.
Nell joins Deeks in the field on a case involving a former Marine who is being tracked by al-Qaida.
In the series premiere, Neil Bremer (Ted Danson) starts his first day as mayor of Los Angeles, where he faces new challenges on the job and at home. Also starring Holly Hunter, Bobby Moynihan, Mike Cabellon, Vella Lovell and Kyla Kenedy.
