As the agents of Graceland strive to close out their ongoing cases and mend broken relationships, Briggs finds himself coerced into a high-risk undercover operation within the Armenian Mafia.

While Mike's visions and addiction to pain medications start affecting his ability to function in the field, Briggs coaxes a former FBI agent out of retirement to help take down Ari.

When Ari Adamian has no recollection of his actions, Briggs helps the Armenian gangster piece together the disturbing details of his lost night.

The death of an agent leaves the housemates reeling; Briggs and Johnny work to rescue Lucia, who's being held by Carlito Solano; and Mike's visions lead him to a small-time crook with a dangerous secret.

Mike develops a plan to learn about the contents of Gusti's trunk; and Briggs helps Paige go undercover with the Armenian Mafia's shipping company.

Plans take a turn for the worse when Charlie attempts to pull Amber from Florida; and in an effort to aid Briggs, Paige sets up a bust to pull the plug on the Sarkissian organization. However, things are not always as they seem.

As Charlie and Jakes close in on Germaine, Mike's drug addiction reaches a breaking point when he and Gusti are caught in a dangerous situation.

While Mike questions Briggs' true motivations in the Sarkissian Case, Charlie devises a new angle to catch Germaine.

Ari rises through the ranks of the Armenian mob; Briggs dodges new suspicions from his housemates; and Charlie and Jakes are one step closer to taking down Germaine.

Johnny goes undercover to stop a gang war; Jakes and Charlie set out to take over Germaine's business; and Mike begins to piece together Briggs' plan.

The feud between the Sarkissians and a local gang heats up; Briggs' motives are revealed; and Mike hunts for the sarin gas.

The agents struggle in the aftermath of the gang war while Briggs tracks down a loose end in order to bring Ari Adamian to justice.