The day's events bring the cops face-to-face with some of their greatest fears. The death of a baby affects Lydia Adams deeply, and Sammy Bryant's altercation with Tammi is scrutinised by Internal Affairs.
The murder of a gang member in Oakland forces Cho to confront his murky past. It emerges that the victim was an old friend of Cho's - and he is willing to go to extreme lengths to exact revenge.