[1] It tells of the exploits of famed onmyōji Abe no Seimei, who meets and befriends bungling court noble Minamoto no Hiromasa.

Together they protect the capital of Heian-kyō against an opposing onmyōji, Dōson, who is secretly plotting the downfall of the emperor.

In Heian-kyō, nobleman Minamoto no Hiromasa meets court onmyōji Abe no Seimei, a mysterious man about whom many rumors have been told.

On a dare by some courtiers, Seimei demonstrates his exceptional skills in onmyōdō by killing a butterfly without touching it (i.e. casting a spell on a leaf which then flies and cuts through it).

Unbeknownst to him, this woman is Sukehime, Minister of the Right Fujiwara no Motokata's daughter and one of the current emperor's wives, who is worried that she is losing the emperor's favor as another wife, Lady Tōko, the daughter of Minister of the Left Fujiwara no Morosuke, had just given birth to a baby boy, who is to be the heir to the throne.

Meanwhile, the head onmyōji of the imperial Bureau of Onmyō [ja], Dōson, is secretly plotting to overthrow the emperor by trying to awaken the vengeful spirit of Prince Sawara, who had died 150 years earlier.

When Dōson curses the emperor's newborn son, Prince Atsuhira, to be possessed by an evil spirit, Seimei combats his spells and drives the demon away with the help of Hiromasa and the immortal Lady Aone, who was ordered by Kanmu to guard the burial mound where Prince Sawara's spirit is sealed away.

They are saved in the nick of time by Morosuke, who points out it is unlawful to kill a court onmyōji without imperial permission.

Seimei shoots an arrow with the paper talisman towards the sky, ordering the curse to go back to its sender.

Dōson, swearing vengeance on Seimei, finally releases the spirit of Prince Sawara from its confinement in the burial mound.

Sawara's ghost enters Dōson's body and summons a horde of vengeful spirits to attack Heian-kyō.