Nintendo began streaming a launch trailer on Friday for the Nintendo 3DS version of Layton's Mystery Journey: Katrielle and the Millionaires' Conspiracy. The trailer previews the game's English dub cast.

The game launched in the West on Friday. The game has been available on iOS and Android devices worldwide since July 20, and the game's Japanese Nintendo 3DS version launched on the same day.

In the game, Katrielle Layton is the daughter of Professor Hershel Layton. The story is set in London, where she solves any incident, from missing cats to murder cases. Her initial purpose, however, was to look for her father, who has disappeared. The game was originally titled Lady Layton: Fugō-ō Ariadne no Inbō (Lady Layton: Millionaire King Ariadne's Conspiracy).

Kuniaki Iwanami designed the game's puzzles, replacing late puzzle master Akira Tago. Kana Nishino performed the theme song.

The Professor Layton game series has shipped 16 million copies worldwide. The Total Licensing magazine reported on Sunday that a television series based on the game franchise is in development.