Find the first gear and enter the upper rooms
Return to the Garage and take the north route into the Lab. Vacuum the blackboard to uncover the ghosts, then catch them for the first stolen gear. Search the loose wallpaper in the Entrance for the Secret Pocket and its key. Continue through the Foyer, deal with the Hider and reach the upper rooms. The mission requires four gears; collecting the first one does not repair the mechanism.
Search the Parlor and Bedroom
In the Parlor, investigate the gramophone and clear the ghosts to recover the second gear. Search the clock with a Strobulb flash for an amethyst before leaving. Continue into the Bedroom and pull down the folding bed to expose the next route. Vacuum loose cloth and inspect the furnishings rather than treating the bed as the mission’s final objective.
Recover the last two gears
Enter the Study and defeat its Greenies and Slammer for the third gear. Pull the rug to reveal the fireplace mechanism, then use that route to the Studio. Catch the hiding ghosts and the Slammer for the fourth gear. While here, look through the camera to locate the amethyst in the high window web, then vacuum the actual gem. Return toward the Foyer with all four gears; E. Gadd discovers that another part is still needed and calls Luigi back.
BaBoon on a return visit
After A-4, replay this mission with Dark-Light. In the Mudroom, reveal the missing table near the foreground wall, then vacuum the Spirit Balls to bring out BaBoon. The Boo is tied to A-2, so finding another Boo during a different mission does not fill this mission’s Boo marker.
Collectible checklist
Gloomy Manor gems — #3 Parlor, #4 Studio
Boo checklist — Mudroom: Return after A-4 and restore the missing table by the foreground wall.