Shea Whigham and Steve Buscemi on 'Boardwalk Empire'

Eli (Shea Whigham) and Nucky Thompson (Steve Buscemi) discover heroin is being smuggled in their rum shipments out of Florida on "Boardwalk Empire." (Macall B. Polay / HBO)

The lure of big money from heroin pits Nucky Thompson (Steve Buscemi) against an odd mix of gangsters on “White Horse Pike,” Episode 46 of HBO’s “Boardwalk Empire.”

“Something’s wrong,” warns speakeasy owner Sally Wheet (Patricia Arquette), tipping off Nucky that partners Vincenzo Petrucelli (Vincenzo Amato) and Meyer Lansky (Anatol Yusef) concealed heroin in a rum shipment leaving Florida.

Outraged Nucky intercepts his trucks at White Horse Pike in New Jersey. Providing backup are Nucky’s turncoat brother Eli (Shea Whigham) and pseudo corrupt Prohibition Agent Warren Knox (Brian Geraghty).

“Are we friends now?” Eli asks Warren, who’s spearheading an undercover crusade to topple Nucky’s criminal network. If Eli doesn’t share useful intel as a confidential informant, his son Willie (Ben Rosenfield) will be “breaking rocks” in prison for poisoning a college student in a revenge prank gone wrong.

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When a thug in the truck caravan resists a search for contraband, Warren promptly shoots him in the head.

“Any other objections?” Warren inquires.

Nucky also threatens violence, forcing Meyer to admit that New York mobster Joe Masseria (Ivo Nandi) is behind the heroin smuggling. And Joe’s new partner is Dr. Valentin Narcisse (Jeffrey Wright), the drug kingpin corrupting Atlantic City’s black community.

“There is money to be made, Mr. Thompson. A great deal of it,” says Narcisse, agreeing to give Nucky one-third of the heroin profits for use of his trucks.

But first Nucky must hand over Onyx Club operator Chalky White (Michael Kenneth Williams), who’s waging an all-out war against Narcisse and his hoods.

“So we have a bargain then,” Narcisse says with a wicked smile. “I see great days ahead.”

Nucky has no intention of betraying Chalky, however. He contacts Mayor Edward Bader (Kevin O’Rourke) and arranges for police to transport Chalky and jazz singer Daughter Maitland (Margot Bingham) safely out of town.

To Nucky’s horror, he learns Narcisse bribed the sleazy mayor, meaning Chalky and his mistress are on a death ride. Fortunately for Chalky, he realizes it’s a setup and kills both cops as Daughter struggles to control the police car.

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Now that he’s chosen sides in the deadly struggle between Chalky and Narcisse, Nucky surrounds his hotel with extra men and prepares for battle. Eli tries to sideline Willie at this critical juncture, hoping his son will switch to a legitimate career.

“This is the life you want?” Eli asks.

“Isn’t it what we do?” Willie replies matter-of-factly.

Nucky’s estranged wife Margaret (Kelly MacDonald) also turns to the dark side when she provides mobster Arnold Rothstein (Michael Stuhlbarg) with inside information regarding an investment scheme. In exchange, Margaret gets rent-free use of a New York City apartment for five years.

“And when it’s over I owe you nothing,” Margaret says to Arnold, sealing his first business deal with a woman. And how is the experience?

“Quite the treat,” Arnold offers.