The third trailer for 300: Rise of an Empire has landed online, promising plenty of action and heroics.

The sequel to the 2007 adaptation of Frank Miller's graphic novel 300, "Rise of an Empire" follows Miller's sequel, "Xerxes," in part -- as the author's graphic novel has yet to be completed.

According to website ICv2, "Xerxes" is a planned five issue series from Dark Horse Comics, followed by a full graphic novel that combines all five issues into one volume. Miller has only two issues completed.

The film opens in theaters March 7, and Miller reportedly has every intention of finishing the series, but his commitments with Hollywood projects like "Sin City 2" are currently keeping him from writing.

The story follows Athenian general Themistocles (Sullivan Stapleton) as he unites Greece to fend off Persian king Xerxes' (Rodrigo Santoro) naval fleet, led by Artemesia (Eva Green).

In addition to Santoro, Lena Headey reprises her role from the first film as Spartan queen Gorgo.