Track Polterpup through the garden rooms
Use Dark-Light on the ground to follow Polterpup’s pawprints. Inspect the Tool Shed hiding place, then follow it into the Garden and check the mower. On returning to the Tool Shed, its furnishings have vanished. Restore the tools, pots, drawers and other missing objects until the Boo appears. One restored object is not enough. Continue up the Toolshed Stairs, clearing the Creeper rather than trying to pass through it.
Finish the chase in the west tower
Follow the trail through the Botany Lab and Seedling Laboratory to the Conservatory. Restore the missing organ and play it to dislodge the dog. Continue through the Crow’s Nest and West Hall, checking the West Bathroom bathtub and the West Bedroom bedding when the prints end there. Approach the exposed Polterpup from behind, flash it and vacuum it before it escapes. Repeat the trail if it gets away. Catching it returns the key needed for Tree Topping; playing the organ alone does not finish the mission.
Collectible checklist
Boo checklist — Tool Shed: After following Polterpup into the Garden, return and restore all the missing tools, containers, furniture and ladder. Keep sweeping until every Spirit Ball is caught and the Boo appears.