Saya is a fairly normal high school girl, except that she has no memory of her life before a year ago and needs regular blood transfusions to stay healthy. She encounters a mysterious man playing a cello whose song triggers a vague memory. When Saya goes to the school that night to retrieve her forgotten shoes, the cello player approaches her holding a dagger. Saya flees and runs into a teacher, Mr. Inamine, who is then killed by a monster. Saya runs into the school, locking the door behind her, but the monster easily breaks through.

The cello player appears and fights off the monster before grabbing Saya and taking her to safety in a classroom. There he tells her the monster is a chiropteran. Meanwhile, her brother Kai arrives to retrieve her after her friend Kaori brings her shoes to their house, and also encounters the monster. The man kisses Saya, forcing her to drink his blood. He tells her "You must fight now."

Under some sort of mindset, Saya laces a sword provided by the cello player with her blood, then strikes and kills the chiropteran before it can attack Kai. Saya awakens from her trance and, seeing her blood-stained self in a reflection, screams "NO!" and faints. The man carries Saya and Kai to safety as American soldiers flood the school. When Saya wakes up in the hospital, she has no memory of what happened.

David tells George  what happened at the school, and rebukes him for being so attached to Saya that he doesn't want to let "them" have her back. Saya starts having flashbacks about the events at the school and goes down to find her father. Overhearing the conversation, she gets upset and runs away from the hospital. At the beach, she meets the cello player again. She asks who and what she is. The man says he will tell her, but before he can, Kai finds her and forces the cellist to leave.

David has given George a deadline to give Saya back to the Red Shield. George takes Saya to his family grave to tell what happened to her one year ago. After returning, they are attacked by another chiropteran, formerly a man by the name of Forest, and George is fatally wounded.

George, having been attacked by a chiropteran and is severely wounded, is currently in the hospital. Kai leaves with his father's handgun to track down the monster, yearning for revenge. The cello player appears again before Saya, and finally introduces himself as Haji.

George has been transferred secretly to a hidden facility in Yanbaru, Northern Okinawa, under the authority of the American forces there.

David, Saya, and Haji infiltrate the Yanbaru Center to rescue George. Meanwhile, the Commander of the U.S. Forces in Okinawa has authorized a surgical bombing of Yanbaru to remove any incriminating evidence. David, Saya, and Haji are suddenly attacked by a chiropteran. George appears and assists the group with combating the monster. Kai arrives later with news that the place is going to be bombed. After being injured by a chirpoteran, George starts turning into one of them; Saya, however, mixes her blood with his so that he can die as a human.

To be continued....

Saya and her brothers are still shocked by the death of their father. Saya asks Haji about her past. He tells her he can't currently say, as she cannot yet fully accept and understand the truth.

Saya is given an assignment to infiltrate a Vietnamese boarding school. Haji goes undercover as the gardener. Saya learns about the "Phantom", who later attacks her. She believes he is a chiropteran but is somehow different than the others.

Left behind by David, Kai and Riku are searching for Saya in Hanoi. Riku and his new friend, Mui, get captured along with Kai.

Saya goes to the forbidden garden and finds blue roses and a mysterious container. Later, she sees pictures of the Vietnam War resulting in flashbacks of her past. While being attacked by the Phantom once again, Saya finally accepts her past.

David and Julia are making use of the opportunity provided by the annual ball held in the boarding school to search for the mysterious container somehow connected to the events in Vietnam 30 years ago. Meanwhile, Saya dances with a charming stranger. Karl, who is the Phantom, attacks them later. David figures out the container holds Diva and they go after it.

The Red Shield has tracked the container to a secret research farm in the Vietnamese jungle. Once they get there, they are attacked by a chiropteran.

Under the mysterious influence of Diva, Saya starts to attack friends and foes alike just like 30 years ago. Kai stops Saya by yelling her name, causing her to regain control of herself. Solomon and Van escape with Diva while Saya fights Karl.

The Miyagusuku family returns to Okinawa to say goodbye to their friends.Ever since returning from Vietnam, journalist Akihiro Okamura is getting more and more obsessed about the events surrounding Saya and his father's encounter with a chiropteran near the Laos border 30 years ago. He is unable to continue his research until he gets unexpected help.

David, Saya, and others enter the Russian port of Vladivostok to board the Trans-Siberian express heading for Ekaterinburg, where a key scientist in chiropteran research was last seen. Before boarding they meet a Red Shield member named Liza. She is later killed by Amshel, who then takes on her appearance. Two chiropterans appear on the train while en route.

Riku is pulled off the train by one of the chiropterans; Hagi and Saya jump off to rescue him. Saya has a dream about her past in 1920s Russia with Hagi, tracking down Rasputin and Diva, who was disguised as Grand Duchess Anastasia.David, Lewis, and Kai's search for a defected Delta-67 scientist leads them to an abandoned nuclear facility called Sverdlovsk-51. Hagi, Saya, and Riku have reached Tyumen and board another train to reach Ekaterinburg.

Saya, Riku, and Hagi arrive at Ekaterinburg to rendezvous with David. Suddenly, Riku falls ill. Amshel (disguised as Liza) questions Saya about her true intentions for fighting the chiropterans.

To be continued....

David and the others arrive at the Red Shield headquarters. Kai learns the truth about Saya from Joel's diary. In France, Amshel, Solomon, James, and Nathan discuss Saya's fate. Okamura and Mao are looking for clues about the '67 vintage wine in Chateau Duel. Saya and Hagi find themselves hunted by a group of artificial chiropterans known as The Schiff.

Saya visits the ruins of Joel's mansion, known as "the Zoo". There, she recalls her first encounter with Hagi.David and the others arrive at the Zoo. Solomon confronts Saya with his side of the story and tries to convince her to join him. Saya confronts Diva after Riku is lured into the bell tower by Diva's singing.Okamura and Mao arrive at The Zoo only to find the end of a broken sword left behind. Saya returns to the Red Shield headquarters with Riku, who is wounded.

Riku's eyes are now open and he is wondering about his current condition, including his incessant thoughts of Saya and his unquenchable thirst. Kai tries to make him eat to prove to himself that Riku is not a chiropteran or Saya's chevalier, but a human. However, Riku is unable to eat much and can't get to sleep at night. The Schiff attack the ship and Riku is injured by one during the fight. After seeing Riku is now Saya's second Chevalier, they flee as Riku burns with pain from needing blood. Kai allows Riku to feed on him and is thanked sorrowfully by Riku for doing so.

In Paris, Kai is recovering from letting Riku drink his blood and finds a member of the Schiff named Irène. After saving her from local street punks, Kai is told about her and the other Schiff's past.While the Red Shield is preparing for another attack by The Schiff, Okamura and Mao suddenly appear. After The Schiff's attack, Saya agrees to share her blood with Irène. After drinking her blood, Irène's body crystallizes and shatters. The Schiff realize that they have been lied to and that it is Diva's blood they need to survive. They leave, taking most of Irène's pieces with them. Saya and Kai mourn Irène's death.

Saya visits Joel's Room at Red Shield headquarters and learns about her and Diva's beginnings as well as the 1972 tragedy in Vietnam from Joel's diary.

While Saya, Kai, Riku, and Hagi go on an outing, Riku tries to repair Saya and Kai's broken relationship. In the meantime, Diva is bored with her toys and demands Carl bring her "that boy," while Dr. Collins and Julia meet with Van about their research into chiropterans. Solomon meets with David and warns him that Diva's chevaliers plan to launch an all-out attack on Red Shield headquarters in three days, and asks him to take Saya to safety. When David asks why, Solomon says it is because he doesn't want Saya to die. Solomon also reveals that the Red Shield has been betrayed from within. David quickly takes Saya and the others back to the ship, leaving Okamura and Mao behind. Solomon and the other chevaliers discover that Carl and Diva have disappeared, much to the anger of Amshel who knew Carl should never be Diva's "babysiter". Dr. Collins reveals to Julia that he doesn't think the chiropterans should be completely destroyed and that he knows about the planned attack on the headquarters. While the Red Shield prepares for the coming attack, Riku convinces Kai to play catch with Saya, which helps them finally return to normal. As they stand on the deck, Saya and Riku hear Diva singing just before Carl (as the phantom) and Diva attack the ship. As Carl begins killing the Red Shield operatives, Diva wonders where "that boy" is.

To be continued....