Darker than Black: Shikkoku no Hana

In Tokyo, the assassin Hei who is escaping from the Syndicate group, and Misaki Kirihara from the Metropolitan Police Department are separately investigating the appearance of superpowered soldiers called Contractors. The soldier Harvest is using a power known as the "Black Dendelion", an item that takes the form of a flower and is placed on human bodies to create the Contractors. He eventually makes contact with a young student named Azusa Tsukimori after she is seduced and betrayed by her coach, Daisuke Mioka. Azusa wishes to become a Contractor in order to lose her strong emotions and gain power to exact revenge.

Hei and his partner Yin locate Azusa who kills Mioka. Hei seeks to kill Harvest due to a request from his previous ally, Amber, whom Harvest worked for years ago. After failing to capture his target, Hei meets Champ and Pancel from the Pandora group who save Yin from enemy forces. Hei learns from them that a remnant of the Syndicate is using Harvet's Black Dendelion to create an army of soldiers and is planning to kill Hei for targeting Harvest.

The police manage to defeat Harvest using weapons from Pandora but Harvest escapes. The Syndicate sends soldiers to retrieve the Black Dandelion from Azusa—who is now weakened as a side effect of the flower. Hei and Yin take Azusa to Pandora to treat her. However, Pandora is attacked by several soldiers from the Syndicate, and Hei, Champ, and Parcel fight them off to let the others escape. While Hei and the Pandora soldiers are victorious, Champ dies in the fight. One of the members from the Syndicate attempts to manipulate a Pandora researcher in order to get the Black Dandelion to continue Harvest's plan. However, Pandora betrays the attacking Syndicate scientists.

After Azusa recovers her strength, she joins Hei goes to face Harvest. The enemy has recovered and is using the dendelion to create his own army, and Azusa's schoolmate, Kyoko, is now a Contractor createad through using the dendelion and a supernatural object used as Meteor Fragment. In their fight, Harvest reveals to be a former ally of Amber and is planning to prove his superiority to Hei, using his new powers amplified by the Meteor. As Kirihara controls the Meteor, Kyoko loses her wrath and Azusa bids her farewell to the afterlife. Meanwhile, Hei is assisted by Yin to control his powers to nullify Harvest, whose body is disintegrated. After saying farewell to Parcel, Hei and Yin leave the city, while Azusa asks Kirihara to arrest her for the actions she committed after taking the Black Dandelion.

Darker than Black: Shikkoku no Hana was written and illustrated by Yuji Iwahara, and was serialized in Square Enix's seinen manga magazine Young Gangan from May 15, 2009,^[2] to January 21, 2011.^[3] Square Enix collected its chapters in four tankōbon volumes, which were released from October 24, 2009,^[4] to March 25, 2011.^[5]