Notes

Set in Victorian England, follows a fourteen-year-old Rori Lovel, the last surviving member of an aristocratic family, as he sells his soul to his devil butler in exchange for the ability to take revenge on his parent's murderers.

It is morning at the grand Lovel manor. Odell Goddard, the handsome yet mysterious butler, is waking his young master for the day. Count Rori Lovel, a fourteen-year-old boy with a gloomy expression and an armband on his left hand, is briefed on the schedule for the day. As his family's heir, Rori is now the owner of the Lovelio Company, England's fastest-growing toy company. Sir Clause is coming from Italy with "the usual goods" (a difficult-to-obtain board game), and Odell oversees the preparations for their guest's visit.
Everything must be perfect to live up to the legendary hospitality of the Lovel name, but the manor's clumsy staff (Tilly, the gardener; Mera, the maid; and Rob, the chef) each bungle their respective areas. Thinking quickly, Odell rescues the evening by covering the dead garden with gravel and changing it into an elegant Japanese rock garden. He serves green tea in place of the ruined black tea, and the burned meat is shaved over rice to make a donburi, completing the Japanese-themed evening for Sir Clause. Odell excuses the praise he receives.

The next day, Rori and Odell leave the manor to buy Rori a new armband. When they return, the manor is decorated in hearts and ribbons, and the staff is awkwardly dressed in bunny ears. When Rori asks what is going on, Diana jumps out and hugs him. Odell explains to the confused staff that Diana is Rori's fiancée. Like many nobles, the heads of their families arranged their marriage long ago.
Diana demands to hold a dance, but Rori sulks. He insists that he must work and does not have time for little girl's games. Odell quickly ascertains the truth, however; Rori does not know how to dance. Odell quickly instructs him in the waltz but says the most important thing is for him to smile. He cannot be a proper noble if he sulks at the sidelines of every ball.
At the dance, Rori wears the clothes that Diana picked for him, but she becomes upset when she sees he is wearing an old ring that does not match the rest of the outfit. When he refuses to take it off, she snatches it from his hand and breaks it. Rori flies into a rage and nearly strikes Diana, but Odell interferes. The ring is a family heirloom, passed down through the generations to every head of the family. Having composed himself, Rori smiles and invites Diana to dance, giving her the ball of her dreams. That night, Odell presents Rori with the ring, magically repaired.
The next day, the staff chases a rat around the manor while Rori plays billiards with a mysterious group. Rori offers to catch a "rat" for one of the men, Duke Harry, but demands that compensation be ready for him when the deed is done. Duke Harry reluctantly agrees, and the party disperses. Soon after, however, Rori is kidnapped from his room.
Rori finds himself the captive of Arturo Vener of the Italian mafia. Arturo, angry with Rori for obstructing the mafia's ability to deal drugs in England, demands to know where the "goods" are. Rori will not cooperate, so Arturo says he will execute his staff. Just then, Arturo receives a phone call: his goons were unable to capture the staff thanks to Odell, and now Odell is hunting them down. Finally, Odell captures them, and they reveal where Rori is being held. He then throws them off a cliff.
Panicked, Arturo fortifies the hideout, but despite all the guards, Odell seems to materialize out of thin air inside the hideout. Easily dodging hundreds of bullets, Odell defeats the kidnappers. In fact, his main concern is that Rori is going to be late for dinner. Shocked, the kidnappers wonder who Odell is; he answers that he is mere "one who is worthy of being the Lovel house's butler."
Having reached the final room, Odell finds Arturo with a gun to Rori's head. Arturo demands the "goods," and as Odell is just about to reveal where they are, more kidnappers appear in the doorway. They shoot him several times. Odell collapses and remains motionless. Arturo says that if Rori were to vanish, the Italian mafia would be free to take over England for their business. However, they will not simply kill Rori. They are going to sell him back to "those perverts."
Just then, Odell rises, holding all the bullets he was shot within his hand. He flings them with the superhuman speed at the kidnappers, and they all drop dead. Terrified, Arturo again holds the gun to Rori's head. Tired, Rori demands to know whether Odell is going to hurry up and rescue him or whether he is going to "go against the contract."
To spur Odell to action, Rori reveals the demonic mark on his left hand (normally covered by the armband), and Arturo freaks out. He pulls the trigger but Odell catches the bullet in mid-air before it can strike Rori. As Odell leaves with Rori, Arturo offers him money to come work for him. Odell reveals that he is a devil bound by contract to serve Rori "until the time when his soul becomes mine."