Chase and August are escorting an annoying accountant named Cecil Rusk - the star witness for the prosecution in mobster Marius Roma's tax evasion trial - to court when they are ambushed by Roma's brother and his thugs. After their car is destroyed, the trio escape on foot through a hail of gunfire. Alone on the streets of Los Angeles, they decide to head out of town, where they believe they'll be safe. But a mole inside the force is leaking information on the detectives' whereabouts to Roma's mob, and it's up to Captain Jensen and Det. Richardson to figure out who it is.