Greek general Themistocles of Athens leads the naval charge against invading Persian forces led by mortal-turned-god Xerxes and Artemisia, vengeful commander of the Persian navy.

After his mother drug overdose, 17-year-old Joshua "J" Cody (James Frecheville) asks his estranged grandmother, Janine "Smurf" Cody (Jacki Weaver), for help, and she invites him to move in with her. Smurf is the affectionate matriarch of a Melbourne crime family that uses her home as a base. Her home is also being watched by cops who are looking for the oldest son, Andrew "Pope" Cody (Ben Mendelsohn), who is in hiding. The volatile middle brother, Craig (Sullivan Stapleton), deals drugs successfully enough to have bought the house for his mother. The youngest brother, Darren (Luke Ford), follows the lead of his siblings, while family friend "Baz" (Joel Edgerton) leads the gang, which specializes in armed robbery.