It's a race against time as the detectives go on the hunt for a sniper whose victims are shot in broad daylight.

Fontana and Green are baffled by a series of flu-related deaths until they discover that the victims were given fake vaccine. McCoy goes after the con man who distributed the vaccine for murder.

Fontana and Green are called in to investigate when Green's former replacement, Nick Falco, is suspected of murdering a young woman he had spent the night with.