Once he read Clark's letter, Layton set off in the Laytonmobile for Misthallery, accidentally ignoring Emmy in his haste. She chased him through London on her scooter. She eventually made him stop by swerving dangerously in front of the Laytonmobile. After explaining who she was (Layton's new assistant, hired by Dean Delmona), they strapped her scooter to the car's roof and went to Misthallery together.
The Laytonmobile remained parked beside the bridge into Misthallery for the remainder of the game.
Layton, Luke and Emmy could be seen packing their suitcases into the Laytonmobile's trunk. They traveled to Montdol on Sharon's request, and stayed there at the Camel Hotel for a few nights whilst solving the mystery.
In the ending, the three can be seen again admiring the view of the city beside the Laytonmobile. They left to go back to London shortly after.
It is parked on a road just outside St. Mystere beside the drawbridge, and remained there throughout the game. It remained inaccessible as a result of the bridge crank being stolen by Bruno.
It does, however, present a puzzle when clicked on after walking to the exit of the sewers.
At the ending, the bridge crank is returned. Layton and Luke left St. Mystere in the Laytonmobile with Flora, who had decided to join them after refusing to take her father's fortune in order to keep the robotic villagers running forever more. She could be seen sleeping on the back seat.
Whilst in the future London at Green Hospital, the elderly Dr. Schrader gave Layton and Luke a set of keys, saying that "the old girl's parked round back". At the rear entrance of the hospital, the two found the Laytonmobile, dilapitated and damaged from being exposed to the weather. Layton failed to start the car, but finds a letter from Future Luke on the passenger seat, telling them to head to the Gilded 7 Casino. They leave the Laytonmobile at the hospital.
It is discovered that the future London is actually fake; being a huge replica hidden in an underground cavern, the clock shop'stime machine actually being an elevator. The broken-down Laytonmobile at Green Hospital was actually a replica built to convince Layton that it was ten years into the future.
Meanwhile, Don Paolo had built another replica of the car using stolen blueprints. After tightening the last screw, he allowed Layton to use it to board Clive'sfortress rampaging across the future London in an attempt to stop him.
After successfully diverting the fortress's power flow with Celeste's help, the fortress began destroying itself. The elevator had ceased working, halting access to Don Paolo's flying machine (how Celeste managed to board the fortress), so the group rushed to the Laytonmobile.
Layton accidentally drove off the fortress, sending the Laytonmobile with everyone inside crashing to the ground. He quickly remembered that Don had mentioned a failsafe if anything went wrong, and clicked a red switch. The Laytonmobile converted into a plane. Layton took everyone to safety in the real London whilst Celeste went back into the fortress to rescue Clive. He rescued the two just as the fortress fell back into the future London and exploded.
The Laytonmobile, appearing in every game, even gives a few puzzles. In Curious Village, by tapping on it at the drawbridge, Layton and Luke must solve "Parking Lot Gridlock". Also by tapping on it at the exit for the sewers, they get the puzzle "Weekend Getaway".
The Laytonmobile doesn't do much else until the third game.
By tapping on it behind Green Hospital, Layton gets the puzzle "The Secret Number". Later on if tapped on again, Luke and the professor get the puzzle "Back and Forth".