In the fourth century AD, Sebastian is a member of the Emperor Diocletian's personal guard. When he tries to intervene to stop one of the Emperor's catamite<nowiki/>s from being strangled by one of his bodyguards, Sebastian is exiled to a remote coastal garrison and reduced in rank to private. Although thought to be an early Christian, Sebastian is a worshipper of the Roman sun god Phoebus Apollo and sublimates his desire for his male companions into worship of his deity and pacifism. Both incense Severus, the commanding officer of the garrison, who becomes increasingly obsessed with Sebastian, tries to assault him, and ultimately presides over his summary execution for refusing to take up arms in defence of the Roman Empire. Justin, one of his comrades in arms, is also in love with Sebastian, albeit necessarily unrequited, but he forms a friendship with the stubborn celibate pacifist. Adrian and Anthony, two of Sebastian's fellow soldiers, are gay and in obvious love with one another.