Chase the book-stealing ghost
Turn the Courtyard staircase toward the upper route and reach the Study. Restore the missing book on the table and place it in the shelf. The ghost steals it, sending you through the Nautical Exhibit. Close the window, clear the fog and catch the ghosts, then adjust the E-Gate’s direction so it connects to the Study. Follow the ghost through the West Gallery and reveal the missing Space Exhibit door with Dark-Light. The Aviation Exhibit’s two balloon sandbags release a diamond, with a ghost encounter between the pulls.
Recover the book and open the Train Exhibit
Look through the Space Exhibit telescope to enter the small-planet fight. Watch the shining trail, flash the exposed ghost and vacuum it while dodging the orbiting attacks. Return with the recovered book through the E-Gate to the Study and put it in the shelf to open the Train Exhibit. Clear the room and inspect the model for the Mario painting reveal.
Before ending the mission, use a purple Bulb from the Study for the optional upper routes. A high Front Entrance gargoyle holds a blue book: flash it, take the book to the Dark Age Exhibit and fill the shelf’s empty slot for a diamond. The Jungle and Ice Age Gold Bulb coin challenges give diamonds; the Dark Age version gives this mission’s Boo. In the Train Exhibit, restore the missing track and ride the small train through its tunnel for the last diamond.
Collectible checklist
Treacherous Mansion gems — #8 Aviation Exhibit, #9 Nautical Exhibit, #10 Front Entrance and Dark Age Exhibit, #11 Jungle Exhibit, #12 Ice Age Exhibit, #13 Train Exhibit
Boo checklist — Dark Age Exhibit: Bring a purple Bulb from the Study and float to the high Gold Bulb. Complete the timed coin challenge and open the chest.