'Boardwalk Empire' Season 3 teaser: Full gangster

"Boardwalk Empire" ended its second season in a very dark place, and this ominous teaser for Season 3 guarantees even bleaker times and more violence in store for Nucky Thompson (Steve Buscemi).

In the slow motion clip, Thompson appears in the rain, shooting a gun at a faceless enemy (a reference to the murder of Michael Pitt's character, Jimmy Darmody -- who was shot by Thompson in the Season 2 finale). Nucky's wedding ring, gun and even his carnation boutonniere fall to the ground along with the victim's body.

As a flicker of gloom crosses Thompson's face, the sequence jumps back, speeds up, and shows Thompson shooting his target again. He scoops up his gun and tucks it away without regret -- the cold-blooded boss audiences have seen him develop into over the past two seasons.

The show's creator already revealed that the upcoming season will skip ahead in time more than a year past Darmody's death, and undoubtedly this promo is promising Thompson's continued descent into callousness, marital problems and murder.

"You can't be half a gangster," it concludes.

"Boardwalk Empire" returns to HBO on September 16 at 9pm ET.