S4, E9: Los Angeles' power grid is taken hostage in a ransomware attack resulting in a citywide blackout; the team discovers the ransomware code used was written by Riley years ago.

Starring Tate Donovan, Sea Shimooka, Holly Deveaux

S4, E9: Los Angeles' power grid is taken hostage in a ransomware attack resulting in a citywide blackout; the team discovers the ransomware code used was written by Riley years ago.