Canaan, a covert agent with the power of synesthesia (ability to combine senses), arrives in China just in time to save her friend, the young photojournalist Maria Osawa, from a deadly attack by the terrorist organization known as Snake.
As Minorikawa realizes Maria has a connection to the mysterious assassin Canaan, they are attacked in downtown Shanghai by a mysterious old man and his young accomplice.
This show centers on three women and their connections to one-another and an upcoming anti-terrorism summit in ShangHai, China. One of them is Canaan, a Middle Eastern assassin and mercenary. Another Another is Alphard, Canaan's rival and also a skilled assassin and mercenary who heads a terrorist organization called Snake. The final girl Maria Õsawa, a victim of an attempted biological terrorist attack in the streets of Shibuya two years previous. Their encounters lead armed interventions between Alphard and Canaan with a deep and tragic history common.
Rescued by her "sister" Liang-Chi, and now taking her place of power as the leader of the terrorist organization Snake, Alphard sets a trap for Canaan, luring her out into the open at a glamorous state dinner.
Minorikawa and Maria receive an invitation to attend the anti-terrorism conference, but it's only a ruse by Alphard to lure Canaan to the summit. Once there, Liang-Chi and Alphard launch their attack, sealing the world's key diplomats in an office chamber, infecting them with the Ua virus--and causing Canaan to rescue Maria, putting her own life in danger.
After the Ua virus is unleashed, infecting world leaders, the global governments have no choice but to allow Alphard to drop a bomb on the anti-terrorism conference, killing millions.
After Alphard chooses Canaan over Liang-Chi, the spurned terrorist breaks off and vows to exact a terrible revenge. Meanwhile, Minorikawa confronts Santana, and is at last allowed to get answers from the mysterious Hakko.
Canaan, Maria, Santana, Hakko, and Minorikawa head to the desert to discover the secrets of the Factory. Once there, Santana confesses his involvement in the massacre, and Hakko reacts with dangerous emotion.
When they enter the Factory's deepest chambers, Canaan, Maria, and the others find the diseased survivors of the horrible experiment. There, Hakko is confronted with her own horrible past.
Alphard kidnaps both Maria and Yun Yun in an attempt to trap Canaan into a deadly confrontation. As both girls hurtle toward certain death aboard a runaway train rigged with explosives, Canaan risks a daring rescue.
After saving Maria and Yun Yun from Alphard's trap, Canaan decides to end their rivalry once and for all. And when Alphard finds out Canaan's inner truth, her own existence is shattered.