Shortly after Baileu Ton arrives in London with her friend Mu Shinyao, the girls are robbed. While pursuing the thief, Ton wanders into Cafe Forbidden, a cafe established by her great-grandmother. Cafe employees Vlad, Luke, and Toryu help Ton search for the culprit. When they find the thief, they transform into inhuman vampires, wolfmen, and vampires... Ton is surprised. However, she learns the ring from her great-grandmother that she always wears holds a major secret.
As soon as the theft is resolved, Shinyao is kidnapped. Ton visits Café Forbidden once again in order to save her friend. With the help of the cafe's fourth employee, Wayne the ghost, and Detective Gregory, the truth becomes clear... and they discover the case involves an inhuman Umbra and the smartphone app "Magic Mirror." Ton waits for the trio to return. However, she receives a notification on her phone that Shinyao is in danger. Ton heads off to save her friend alone.
Having defeated the serial killer Umbra, they search the building, but Shinyao has vanished. While searching for her whereabouts, Ton learns the four employees of the cafe are members of the Twilights, an organization that seeks coexistence between humans and shadows, and Cafe Forbidden is the organization's London branch. They blindly continue the search for Shinyao, but only Luke seems to recognize a trace left behind by the culprit. Luke secretly heads out to meet the man who kidnapped Shinyao... where he meets Chris, a young man he knows well.
Though Chris kidnapped Shinyao at Haysin's request, he's now taken her to his hideout in order to protect her. Meanwhile, Ton grows closer to the members of the Twilights while investigating her friend's kidnapping and learns Toryu the jiangshi's talisman hides a secret. When his talisman is removed, Toryu becomes a weapon bent on destroying everything before it finally self-destructs. When Toryu's creator removes his talisman and makes him lose control, the Twilights desperately try to stop him. Just when they think they're out of options, Ton uses the power of her ring and attempts to stick a talisman on Toryu, but...
Having cut ties with Haysin, Chris and Shinyao hide together in an abandoned hospital. As Shinyao is dependent on Chris, he begins to see her as more than just the human he kidnapped. Meanwhile, Ton is visited by a beautiful woman named Lydia as the new manager of Cafe Forbidden. Lydia is a leannán sídhe, an kind of Umbra that must never take a human lover. Oblivious to this, Ton accepts her request to find her a human lover. Wayne finds the perfect match for Lydia's criteria, but... he's popular musician Roland Lee. He is actually Lydia's ex-boyfriend and still hasn't been able to forget her. Roland visits the cafe to meet Lydia, but...
Thanks to Wayne, the members of the Cafe successfully determine Shinyao's location, but Midnight Sun, the Umbra extermination organization led by Van Helsing XIII, capture Shinyao and Chris first. Ton and her friends fail to rescue Shinyao again. However, Helsing tells Ton he will return Shinyao to her if she accepts his conditions: cease all contact with Umbra and forget about the incident. Helsing's words leave Ton unsure what to do... That night, Ton leaves the Cafe.
Ton and Shinyao are reunited. They attempt to return to the cafe, but instead are confined within the room. They're able to escape with Wayne's help, but he becomes trapped inside a computer by the developer of the Magic Mirror app. While Vlad and Helsing are fighting, Haysin appears before Ton and Shinyao. Haysin claims to be the mastermind behind the series of events and commands an Umbra to attack her. When Ton sees Shinyao fall from the building, the shock causes her to lose control over the power in her ring.
After losing control over her power, Ton collapses. Though she finally awakes, drawing too much power from the ring has caused her to lose her memories of Shinyao. Should she reclaim her memories and use her powers to fight for her friend once more, or would it be better for her to give up those memories and live as an ordinary human...? Concerned for Ton's happiness, the various members of the Twilights express their toughts to Ton. Meanwhile, Shinyao and Chris continue to flee from Midnight Sun. The Backup, who has been observing them, realizes Shinyao has a strange and mysterious power. When Haysin also expresses interest in her power, the Backup proposes a game.
The Twilights, Shinyao, and Chris agree to meet in secret so they won't be noticed by Midnight Sun. Meanwhile, Haysin and the Backup's game begins: a contest to see if Haysin will awaken Ton's powers first, or if the Backup will awaken Shinyao's powers before him. Ton disperses her pursuers as she closes in on Shinyao, but she's stopped by the powerful Umbra Haysin has unleashed on the city. She's forced to choose between Shinyao and the lives of the city's residents. Meanwhile, despite their efforts, Shinyao is captured by the Backup's soldiers, and Chris falls into the river when he's shot full of silver bullets...
Problem solving app "Magic Mirror" turns out to actually be an app for manipulating people. Shinyao falls into the hands of app developer Backup. When she absorbs Umbra in an experiment, they learn she can gain their powers. Satisfied with the results, Haysin and Backup agree to wager Ton and Shinyao in a final battle. Meanwhile, at their hideout, the members of the cafe stiffen their resolve in preparation for the final battle. Their goal is to reunite Ton with Shinyao as a human. However, Ton, who has regained her power and is on the verge of becoming an Umbra, ignores Vlad's attempts to stop her and tries to go save Shinyao...
The Twilights and Ton head to the Tower of London, a treasure trove of Umbra, in order to save Shinyao. The Twilights face off against the countless Umbra Haysin has prepared for them. Meanwhile, Wayne and Ton find Shinyao, but she has transformed, having already absorbed many Umbra. Shinyao mercilessly attacks her friend Ton. Wayne is struck while protecting Ton. As Ton attacks Shinyao, a man thought to be her enemy comes to her rescue: Van Helsing.
Luke, Toryu, and Chris battle against a golem that Haysin repeatedly resurrects using his life energy. Meanwhile, Ton learns she can stop Shinyao by destroying the device inside her body. She tries her best to do so but fails. Just as she's about to give up, Vlad appears and successfully removes the device from Shinyao. However, having used too much of her strength during the battle, Ton is one step away from becoming an Umbra. Vlad tells her to return to him and breaks his century-long taboo, inching his sharp fangs towards Ton's neck...
