Hour Three: no light may show
Nudge. Cross out every room on the warden's slate. Then find the way that is left.
Harder
The library, the passage and the scullery show light, and the warden is at both doors. From the cellar stair the still-room leads nowhere; go the other way, along the bottom row and up through the kitchen.
The hour, in words
The fire plan is a grid of twelve rooms in three rows of four. Top row: Library, Hall, Dining room, Front door. Middle row: Still-room, Passage, Kitchen, Scullery. Bottom row: Cellar stair, Boot room, Larder, Back door. You start on the Cellar stair. Tap the next room you walk into, one step at a time, up, down, left or right; each tap is added to the line marked The way so far. Then tap Cross the house. Back one undoes a step and Start again clears it.
The answer
The answer is a3-b3-c3-c2-c1-b1.
With the library, passage, scullery and both doors ruled out, the only way from the cellar stair to the hall is boot room, larder, kitchen, dining room, hall.