A phantom thief named Rusty Nail sends a letter to a mansion, saying they're going to steal their treasure. The Mikuni Detective Agency is called to protect the treasure, but are they up to this challenge?
You were always like that, 
weren't you, Nii-san?
Das hattest du so geplant, oder, Nii-san?
Tú siempre has sido así, ¿verdad?
Siempre estás igual, ¿eh?
Tu es sans cœur,
grand frère.
Você sempre foi esse
tipo de pessoa, né, maninho?