On Sunday night Boardwalk Empire shocked fans with a few unexpected turns, and with only two episodes left in the series the HBO drama promises more surprises to come.

Stephen Graham Dishes On Al Capone & 'Boardwalk Empire'

According to new HBO preview (featured below), things will be moving very fast during the last two installments of the prohibition drama's shortened fifth and final season.

"You have crossed the line," warns Nucky Thompson (Steve Buscemi) during a heated telephone call, which probably has something to do with his consent to Mickey Doyle's (Paul Sparks) preparation for war.

Creator Terence Winter Talks Murder On 'Boardwalk Empire'

On the run from Al Capone (Stephen Graham), Eli (Shea Whigham) will be confronting his eldest son, who wants nothing to do with him but may have no choice when he's kidnapped and subsequently tortured.

The next two episodes also promise to expand of Nucky's relationship with Jillian Darmody (Gretchen Mol). On Sunday Jillian was introduced during a flashback as a kid living on the streets, pretending to be a boy and stealing from the boardwalk shops to survive.

It's been known from the beginning that Nucky was the one who brought Jillian to the Commodore, whose sexual assault of the minor led to Jimmy Darmody's (Michael Pitt) birth. Flashbacks over the next two weeks intend to show how these events played out, as well as their impact on those involved over the next few decades.

Episode 6 was a bloody one as the program bid farewell to two series regulars who've been around since season one. Nelson Van Alden (Michael Shannon) met his end halfway through, while fan-favorite Chalky White (Michael K. Williams) found peace in death during the last few moments of the episode. Episode 7 promises to be just as dangerous, with enemies at every turn.

"We are on our own here," warns Nucky during the last few seconds of the 35-second preview.

Boardwalk Empire continues on HBO with the remaining episodes of its fifth and final season Sundays at 9 p.m. ET/PT.