Billy, the son of the preacher, secretly falls for a mysterious and pretty new parishioner. Constrained only to be able to look at her during Mass, he slowly lets himself punctuate the ceremonies with bits of his fantasies, giving rise to a succession of eclectic, often romantic, but sometimes naughty thoughts.

Based on Frank Miller's graphic novel, "300" is very loosely based the 480 B.C. Battle of Thermopylae, where the King of Sparta led his army against the advancing Persians; the battle is said to have inspired all of Greece to band together against the Persians, and helped usher in the world's first democracy.