Layton's Mystery Journey: Katrielle and the Millionaires' Conspiracy is a Nintendo 3DS puzzle adventure game from the Layton series. It centers on Katrielle Layton and a mystery storyline built around the Millionaires' Conspiracy.

• Cleaned, tested, and guaranteed to play. Authentic cartridge.
• Educational puzzle gameplay combines brainteasers, logic challenges, and deduction-driven case solving.
• The story follows Katrielle through a London-set investigation with a lighthearted mystery tone.
• Plays in 2D on Nintendo 3DS systems, matching the display note for this release.
• Developed by Level-5, the studio behind the Layton puzzle-adventure series.

This entry shifts the series focus from Professor Layton to Katrielle Layton, giving the 3DS release its own lead detective and case structure within the larger Layton franchise.