Having read the third letter left by Luke from ten years in the future, Professor Layton follows his instructions to the Gilded 7 Casino at Flatstone Street.
The casino[edit]
Make your way back to the station, then take the train back to Flatstone Street. Back on the street, there is no sign of a casino, so you will need to ask the locals about its location. Talk to Berta to trigger Puzzle 019. Move south and talk to Hazel, who is once again intimidated by Layton. Move west to the hotel and enter it. Talk to Becky, who will tell you that the Gilded 7 casino is north of Flatstone Street, and is a Family hangout. Exit the hotel and move west, then talk to Max for Puzzle 024, which will net you a 
mushroom sticker. Move east two times, then check the bird flying in the sky.
Move north once more, then move into the street once guarded by a Family goon to trigger a cutscene. Layton seems to recognize a lady who happened to walk past him. After the cutscene, talk to Ward for Puzzle 026, which will net you a 
cocoa sticker. Move north and check the fountain multiple times to trigger hidden Puzzle 144. Try to enter the casino to trigger Puzzle 027.
After a cutscene of Layton meeting future Luke, he will challenge Layton to a puzzle battle to prove his identity!
Puzzle Battle 1: Layton vs. Future Luke[edit]
Four cards sit in a line.
- A heart is next to a diamond.
- A club is not next to a spade.
- A heart is to the immediate right of a club.
Tap the spade.
Layton in the future[edit]
After the battle, Mystery 5 will be solved. Future Luke will take us to the casino's supply room. Talk to Luke there, who will inform the group that London in the future is ruled by an evil Layton! Mystery 4 will be solved. Future Luke will go on to explain that soon after the failed time machine experiment, Dr. Stahngun went into hiding to avoid capture. Professor Layton gave him shelter, and soon grew distant from Luke. He started becoming obsessed with time travel, and used his intellect to control London's underworld, using the money he gained to fund Stahngun's research.
Stahngun eventually built a newer time machine, the one in the clock shop on Midland Road, opening a wormhole between the present and the future. Layton is now traveling back and forth through time to bring time travel scientists to work on an even better time machine, and future Luke needs the present Layton to stop his future self. Finally, Luke will mention that there was never a scientist called Stahngun, meaning that the scientist who invented the time machine used a fake name. Mystery 1 and 6 will be solved, but you will get Mystery 7: Future Professor Layton and Mystery 8: Who Is Dr. Stahngun?.
After the conversation, move out into the lobby. Try to exit the casino to trigger a cutscene. Layton will be stopped by a member of the Family and targeted by goons wielding machine guns! Puzzle 028 will automatically trigger. Using the crafted slot machine gun, Layton manages to drive the Family back, ensuring their escape! After the cutscene, you will get the 
Big Score course.