Plot

Alexx's son is a central figure in a murder investigation involving drug dealers, and Alexx does everything in her power to help and protect him.

While jet-ski racing in Miami harbor with Mary Landis, who says they met that morning, Jim Farber, just released after 8 years jail, is fatally hit in the head by a fairly rare Flagstone slate from a bridge above and falls off. He was on pills, Y2K drugs which were confiscated years ago, making them got hem jailed. A marking traces the customer-made garden slate to Henry Woods, Alexx's ex who denies any knowledge, so she questions their son Bryan. Henry finds a cigarette bud there, from Bryan's white teenage friend Trey Holt, whose juvenile record shows throwing a rock trough a window. Next Brian calls in panic from a warehouse, in a pool of blood from Trey's body, saying he just pulled he knife out as his friend begged. Yet after her arrival Bryan runs, is caught with drugs he was 'just throwing away', refuses to say whom he got the poison from. The knife has Mary's DNA, she confesses the stabbing as drugs-related. Everything changes again when Trey discloses his secret deal with Agent Brad Sylvestri.—KGF Vissers

Rock music blares as two jet skis navigate the Miami waters.

Two water-sport enthusiasts are racing. They agree to go best two out of three. The music turns ominous. The man races under a bridge out of view. There is a thump. The woman looks back. The jet ski is empty. The man is gone.

Frank is on the scene. The dead man is pulled from the water. The girl, Mary Landis, explains that her competitor might have crashed into the pylons, but she isn't sure. She doesnt even know his name, having just met the victim that morning.

Caine arrives on the scene along with Alexx, who notices major skull damage.

"There's an awful lot of blood on that jet ski, Alexx," Caine growls. "I don't think he was thrown. I think he died on it."

Alexx discovers dark flakes in the victim's hair.

"He didn't hit something," she says. "Something hit him."

Caine looks up at the bridge.

"So we have death from above," he growls.

Cut to opening credits!

Back at the beach, divers enter the water while Calleigh and Alexx examine the body. Calleigh has identified the man as Jim Farber, who has recently been released from prison. The divers, meanwhile, have discovered two larges pieces of slate in the water.

FLASHBACK: the slate falls from the bridge, striking the victim on the jet ski below.

Calleigh notices writing on the slate pieces.

Eric doesn't know what the writing means, but looks pleased regardless.

"I think we just found our murder weapon," he says.

Ryan and Natalia comb the bridge. Ryan spots something: a white pill near the guardrail. The pill sports an readable logo.

One montage of Ryan examining the pill later, the logo is identified as "Y2K." Natalia notes that the Federal Narcotics Division had seized the entire supply of the drug in 2000. The supplier: Jim Farber.

Calleigh heads to the FBI. Agent Sylvestri tells Calleigh that the killer could be an unhappy customer or even a competitor.

Caine and Natalia go to see a slate salesman. The color is October Dust, a rare brand. He explains that sometimes customers mark the slate as a reminder of where to place a piece on a property.

"Do you have the customers name?" Caine growls.

The salesman says the slate was signed for by Henry Woods -- Alexx's husband.

Back at the lab, Eric and Alexx examine the slate. Alexx reads the writing: "Left walk Jamie window." Eric leaves. A concerned Alexx pulls out her cell phone. Something is clearly wrong.

Bryan, Alexx's son, enters the lab. She tells her son that a piece of slate from their backyard was used in a murder.

"Who have you had over to the house recently?" Alexx asks her son.

Bryan denies any involvement, saying that "Mr. Caine" visited the backyard that very morning. Alexx is shocked.

FLASHBACK: Caine picks up a cigarette butt from the yard.

Caine asks Maxine to run a test on the cigarette butt. One montage of Maxine running a test later, she gives Caine a name: Trey Holt.

Caine brings in Holt for questioning. The arrogant teen says Bryan is a friend. The two hang out and smoke when Alexx isn't home. Caine explains that a piece of slate from the yard was used to kill a man.

Trey says he doesn't know anything about that.

Back at the morgue, Alexx gets a call from Bryan. Bryan says he is "in trouble" at a nearby warehouse. Alexx rushes out.

Arriving at the warehouse, Alexx moves carefully through the stacks of cardboard boxes. She hears a groan and begins running. She finds Holt on the ground, bleeding. Bryan drops a knife.

"What did you do?" Alexx whispers.

"Nothing!" Bryan says. "I swear!"

Bryan claims to have pulled the knife from his friend. Alexx frantically attempts to stop the bleeding, telling her son to go wait in the car. Alexx calls an ambulance.

Sometime later, Holt has been stabilized. His body is being taken away by paramedics when Eric arrives. Alexx explains to Eric that her son pulled the knife out of Holt. The two rush outside but Bryan is gone.

Alexx pleads with Eric not to run prints on the knife, as it would surely implicate Bryan. Eric agrees to hold off for now. Alexx jumps in the car to look for her son.

Back at the lab, Eric tells Natalia the situation. She runs a DNA test on the knife. The DNA matches Mary Landis, the jet skier from earlier.

Frank and Caine question Landis. They suspect her of stabbing Holt in the back. Mary quickly folds, explaining that she paid Holt for Y2K pills, but he never delivered. Also: Mary knew the victim all along.

"You lure him to the bridge and Trey drops a big rock on his head," Frank explains.

Frank gets a call. Patrol has spotted Bryan.

Cut to a Crime Scene Investigation Hummer racing along the mean streets of Miami. It stops on the same bridge from earlier. Bryan drops a paper bag. Ryan opens the bag to find a plastic bag inside filled with dozens of Y2K pills.

Caine reluctantly interrogates Bryan along with Alexx. Bryan refuses to give up the name of the person who provided him with the pills.

"I'm sorry about this, Horatio," says a shaken Alexx. "But this interview is over."

Eric examines the plastic bag. One montage later, he announces his findings: the fingerprints match those of agent Sylvestri.

Caine goes to see Sylvestri. The agent explains that he delivers bags of phony drugs to prearranged contacts all over Miami, so it makes sense that his prints have shown up.

"Druggies reuse bags all the time," says the agent. "You'll probably find a hundred of them with my mitts on them."

Alexx visits her son in a holding cell. She tries to convince Bryan to talk.

Bryan, breaking down, explains that Holt asked him to come to the warehouse. After pulling the knife out, Bryan received instructions from Holt to take the pills before Mary could. Holt also took the slate from the Woods' backyard. Crying, Alexx embraces her son.

Calleigh visits Holt in the hospital. Holt admits to taking the slate and dropping it on Jim Farber. He says the Feds set him up. Holt signed up to be a snitch along with Mary. They got all the pills they wanted as long as they delivered the names of sellers to the FBI. But the deal was soon changed.

Holt says Sylvestri told him to kill the victim or go to prison.

Caine confronts Sylvestri, who denies involvement in the murder. Eric explains that when Sylvestri seized the Y2K pills from Jim Farber in 2000, the agent kept some in order to bribe junkies into working for the FBI. Once released from prison, Farber threatened to expose the agent, so Sylvestri ordered him killed.

Case closed.

Back at the lab, Caine visits Alexx. He explains that Bryan will be released that day. Alexx, fighting back tears, explains that she is resigning to spend more time with her family.

"It has been my honor to work with you, Mr. Caine," she says.

"Back at you," Caine growls. "And, Alexx, that door will always be open."