Butt Detective the Movie: Mystery of the Ruins of Tentōmushi

The Case of the Courageous Curry. On a sunny afternoon, Butt Detective and his assistant Brown are enjoying a leisurely afternoon tea at the cafe. Mr. Walter, the manager of a new curry restaurant in town, walked in with a large shopping bag. At this time, he found that the spices he had just bought, “Piriritokikku", an essential spice for curry dishes, had disappeared from his shopping bag. “You can't make curry without the spices! There is no way to open the business on schedule!” While Mr. Walter was devastated and distressed, Butt detective step forward, his remarkable reasoning mind is ready to solve the disappearance of the curry spices.

The story follows Butt Detective and his assistant Brown as they solve a difficult case on Souffulé Island, where people ride the wind and fly in the sky.

A baffling series of crimes turns out to be the work of Shiriarty, a villain who seeks to steal a mysterious treasure known as the "O-PARTS". Oshiri Tantei along with his assistant, Brown, enlist the aid of Audrey, an investigator from the international police organization Wanterpol, in an effort to prevent the "O-PARTS" from falling into the wrong hands while Shiriarty strives to plunge the world into darkness.

The magazine "Cafe Guide" comes to "Cafe Lucky Cat", located on the first floor of the Butt Detective's office, for an interview, but the owner hurts his back, so Butt Detective takes over as owner for the day. The interview was going smoothly when a huge amount of sweet potatoes, eggs, fresh cream, and butter that the owner had mistakenly ordered arrived at the shop. Butt Detective and his team are surprised by the mountain of ingredients. In order not to waste the ingredients, Butt Detective decides to work with everyone in town to make a super-sized sweet potato.

Butt Detective's partner who disappeared 10 years ago suddenly reappears. He receives a mysterious message from Suisen and soon finds himself embroiled in a case of counterfeit art involving a massive plot to shake up the art galleries around the world.

Story begins when Koala asks Butt Detective to find a missing relative who disappeared from an idol contest. The case takes Butt Detective to Stardust Island, the site of the contest, and also the home of the international criminal organization Phantom Thief Academy, headed by Phantom Thief G. Here, the organization advances its secret conspiracy, codenamed the Dark Age Plan. Butt Detective enters Stardust Island under the guise of an idol. At the same time, he joins forces with Phantom Thief U, who is out to steal back the valuable Moonlight Stone from Phantom Thief G. The story will also reveal more about Brown's past.