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.

Following the success of the Dawn Rebellion, Degwin negotiates with Vice Admiral Revil to surrender all Federation assets and the complete withdrawal of Federation forces from Side 3 to prevent similar incidents from happening again. After bring reprimanded by Degwin for failure to look after Garma, Dozle sends Char - who motivated Garma into starting the rebellion - to Earth; in response, Char requests to become a mobile suit pilot when he returns. Feeling the burden of his responsibilities, Dozle proposes to cadet Zenna Mia. In the Earth city of Manaus, Char lands a job as a mobile worker pilot at a construction site. He meets a young Lalah Sune at a casino.

Hinako is a surf-loving college student who has just moved to a small seaside town. When a sudden fire breaks out at her apartment building, she is rescued by Minato, a handsome firefighter, and the two soon fall in love.

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.

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.

Mystery of the Ladybug Ruins. Here comes the second piece of “Butt Detective" jumps to the big screen. This is an adventurous action film that tells the story of the Butt detective and his father Butt Dandy discover the mystery of the ancient ruins together! One day Butt Detective received a commission from his father's Butt Dandy, which is going to the Ladybug Ruins to investigate into a case. According to the rumors, the hidden treasure in the ruins, possibly could save the continuous drought in the dim dim village. Butt Dandy and a baby panda called Tan arrived to the site in advanced, however someone who wants to steal the treasure are already onto them. Moreover, the phantom thief U delivered a criminal notice at the same time. Butt Detective follows the footstep of Butt Dandy, while unraveling various mysteries in the ruins!