Detective Opera Milky Holmes

After some pushing by Irene and her father and a lack of support otherwise, Kokoro stubbornly quits her job as a police detective to become an idol. She soon finds the idol life draining and starts to miss her old detective life. When Henriette notices Sherlock's loneliness without her, she stages a statue theft in order to convince Kokoro to return to the force.

Set in the same universe as the PSP games, Milky Holmes arrive in London where they meet a girl called Lily Adler, who seeks the help of their old mentor, Opera Kobayashi, to search for a painting of her grandmother that was stolen from her home. Taking on the case, the gang learn there have been several other related robberies in which paintings were stolen. As they interview the victims, they start to piece together how the paintings are related. They soon encounter another victim who was robbed, who believes the culprit to be an invisble man. Through careful deduction, they discover the culprit is the owner of the fifth painting in the set, Adiele, who is revealed to actually be a Gentleman Thief named Kitty Evans. Kitty attempts to escape using her Invisibility Toys, she is thwarted thanks to the combined efforts of Milky Holmes and Lily. As Opera tries to get Kitty to reveal her motive, she is hit from afar by something which causes her to lose her memory.

During an encounter with a group of Gentlemen Thieves, the ace detective group Milky Holmes suddenly lose their Toys, which give them special abilities. A month later, they have since descended to being the worst student at Sherlock Holmes' Detective Academy. The Gentlemen Thief leader, Arsene, masquerading as the Student Council President, moves Milky Holmes into a less luxurious lifestyle inside an attic and gives them three months to recover their toys before they are expelled.

As the Gentlemen Thieves continue their crime spree, Milky Holmes are having trouble adjusting to the poorer life. Cordelia Glauca tries to convince everyone to be friends, but inadvertently makes things worse. Everyone's mood soon livens up when Sherlock Shellingford finds a stray kitten, naming it Kamaboko. When Kamaboko starts pilfering bread from the cafeteria, Milky Holmes are accused of stealing it. Wanting to protect the kitten, Cordelia takes the blame. In order to save Cordelia from expulsion, Milky Holmes investigate the crime scene, finding the true culprit and the reason Cordelia protected him. Learning the truth, Henriette revokes the expulsion and allows them to keep the cat.

When Milky Holmes go to assist the guarding of a statue targeted by the Gentlemen Thieves, they are teased by the anti-Gentlemen-Thief force, G4, with false promises of getting their toys back. When Hercule "Elly" Barton fails the ridiculous ritual set by the G4 leader, Kokoro Akechi, Nero Yuzurizaki gets angry at her. When Arséne steals a fake statue, G4 try to follow them with a tracking device, but Milky Holmes accidentally breaks their computer when Cordelia gets scared. Still sad about earlier, Elly runs off so the others go look for her at the museum, where they run into the thieves who are trying to find the real statue. During the fight, Cordelia and Twenty get trapped in a sarcophagus, but the embarrassing noises temporarily gives Elly her toy back allowing her to get them out.

Milky Holmes have been neglecting their roles as detectives to tend to a vegetable farm they have been working on, which irritates Henriette who wants them to work on regaining their Toys. Noticing Henriette's depression, the Gentlemen Thieves take it upon themselves to get revenge on Milky Holmes by wrecking their vegetable farm, though this ends up evoking a murderous rage within them. After Milky Holmes are reminded about their roles as detectives, the matter is settled following a few explosions and Henriette's order to destroy the farm.

As Milky Holmes laments the loss of their farm, Hercule notices their Toys have returned, with the others oblivious to the fact. Hercule is later given a strange painting from her part-time job, which peaks the interest of a wealthy man as it reminds him of his long lost wife, offering a large sum which Nero accepts. However, a wind blows it away, leading to a rampant chase throughout town, with everyone besides Hercule oblivious of their use of Toys. The soon find the painting underneath a beached whale, which Hercule manages to lift off using her Toys, launching it into a pirate ship that held the man's long lost wife hostage. After eating some sushi, which Hercule forces Nero to use her money to pay for, the girls return home to learn from Henriette that the Holmes Detective Academy may be shutting down, the shock of which causes them to lose their Toys again. Hercule reminds the others of their duties as detectives and together they start thinking of a way to save the academy.

Milky Holmes decide to go explore the Hakkei Prison Island to find a way to save the academy, but they are captured and imprisoned on arrival. Meanwhile, Henriette and the Gentlemen Thieves have also infiltrated the island in search of a legendary treasure. After hearing about the treasure from an old man, Henriette, along with Milky Holmes, stage a breakout, but end up falling into traps by the prison guard. However, they manage to find their way out and soon find the treasure is a single flower which, when removed, reduces the prison into a pile of sea cucumbers, only to later realise they had set a bunch of criminals into the city.

Alice and Kazumi are two friends who aspire to become great detectives like Milky Holmes. Whilst on a day out, they spot a thief and decide to pursue him. Although his escape is thwarted by the arrival of Milky Holmes, he is retrieved by other members of a group of thieves calling themselves Colors Phantom.

Alice and Kazumi decide to sneak into Holmes Academy for a chance to see Milky Holmes, where they end up getting inadvertently knocked out by them. As the two state their desire to be just like Milky Holmes, they simply respond by saying if they want it, they should just do it, whilst trying to keep up a classy image. Later that night, Alice and Kazumi encounter the thief from before, donning their new detective uniforms to fight against him. Whilst Kazumi's Arrow Toys prove to be ineffective, when combined with Alice's Barrier Toys, they combine into a powerful arrow that knocks the thief out. The girls leave the thief in the custody of the police, leaving behind a calling card naming themselves "Feathers".

As word about Feathers spreads, receiving both support and criticism, Kazumi feels irritated when her teacher passes them off as 'fake detectives'. Whilst Kazumi has dinner at Alice's house, one of Color the Phantom appears during a television chat show, threatening to take the license of detective named Komatsu Ryuko. Alice and Kazumi decide to sneak out, later finding Komatsu with her license allegedly stolen by one of the Phantoms. As they go search for it, they are lured into a trap in which Alice is seperated from Kazumi, who finds herself up against the illusionist, Blue Phantom, and being completely surrounded by his illusions.