In the 'Cuda, Joe informs Nash that his nephew the lawyer - Latio, is on the case of Joe's bad house deal. Nash mentions that he had Cassidy transferred to a safe patrol gig out in Seacliff.
But then Nash and Joe spot Cassidy walking along - undercover as a prostitute. At the Paragon Restaurant, Cassidy is arranging a meeting between some buyers and a fence. Suddenly, a sniper shoots one of the buyers, forcing Nash to shoot one of the fences. The other buyer escapes, the remaining two fences escape, but not before Inspector McCabe fires some shots at the fences. Nash and Joe go search for the sniper, but Cassidy disobeys and encounters the sniper first. She is slugged as the sniper escapes.
The buy/bust has gone bad. Dead are Joseph Taylor, South African chemist for the Stellingbach Diamond company. Inspector Rachel McCabe informs Nash that she was after D'Tone, the fence who escaped. Another South African is identified as associated with Taylor, Dirk Van Der Goes, a wholesale diamond dealer. Nash meets with the Deputy Chief, who has placed Cassidy undercover and in harm's way, against Nash's wishes.
The diamonds left behind at the crime scene are high quality synthetic diamonds. It appears that Dirk is out to stop these synthetic diamonds from flooding the market. Through a realtor connection to Taylor, Antwon and Harvey discover the location of the synthetic diamond factory, along with two dead bodies. The same sniper as before has struck again.
The other buyer is identified as Rick Hamilton from a passport left behind at the factory. Hamilton is brought in, but refuses to talk. Meanwhile, Cassidy and Rachel catch D'Tone. Nash interrogates both D'Tone and Hamilton, playing one against the other. But before they can talk, the sniper strikes again, killing D'Tone and wounding Hamilton in the ear.
Dirk meets with the sniper, and garrotes the sniper in his car. A safety deposit box key belonging to Hamilton is found to be filled with diamonds. Mistakenly, Cassidy and Rachel try to roust Dirk by telling him he is next on the sniper's hit list. The sniper's body is found, as Nash decides to set up Dirk. Nash asks Dirk for one million dollars, in exchange for the location of Hamilton. Dirk shows up to kill Hamilton, but the SIU is waiting.
Joe's latest off-duty case involves a supply of expensive wine being held for ransom. Joe tests the probable suspects by pretending to almost drop a bottle of valuable wine. Only the stock boy Denny does not rush to catch the falling bottle, proving Denny does not care about wine, and that Denny is the culprit. Joe catches Denny at the money drop with the wine case full of cash.
With the help of his nephew the lawyer, Joe almost gets out of his bad house deal. But just as seller Gertrude Jorgensen is about to sign the purchase annulment, she dies before signing, leaving Joe stuck once again with the rotted out house.
Cassidy and Rachel decide to join the SIU, to cover up for the wire tap they placed on Dirk without Nash's permission. Nash refuses Cassidy and Rachel, but the Deputy Chief forces the issue with Nash, so Nash changes his mind to annoy the Deputy Chief. Cassidy and Rachel become part of the SIU as Nash signs their transfer papers.
For more, see commentary for Episode 102