The Winterbourne house was a place of gently threadbare carpets on cherrywood floors, and deep cushy sofas covered with tapestry pillows, and Colonial sideboards piled with old pewter, and ivy in terracotta pots drifting across dusty window ledges. It was as though New England had gone to sleep and dreamed of a house. Such a dream would need a large house, and so the Winterbourne house was. It rambled back from the street and up the hill and then back down the hill again, then turned at the treeline, engulfed an old potting shed, and took a tour of the edge of the forest.

Inside it was even more rambling. At the front there were the two old parlors, best and family, the drawing room, the morning room, the huge dining room from the Victorian age, the smaller dining room from the Edwardian, the kitchen (which was two rooms knocked together, and had two couches and a Colonial fireplace), the scullery, butler's pantry, and all the rest of the warren of little servants' rooms--they were rarely used, and tended to get jumbled up if not visited often enough. Then the old study and the long, four-room stretch of library, which took up the entire north side of the first floor; a second morning room; the orangery; the greenhouse; the conservatory; the music room; and the cabinet of curiosities. There had once been a smoking room, but it was lost now.

Even with this wash of rooms, the four present Winterbournes had to take care not to be in one another's hair too often. It was all very well to stake out the outer reaches of the library, as Quin had done, or the first morning room, as Mariah had done, but everyone wanted the kitchen. So, after a long morning of slapping hands away from her baking, Ariel was at the breaking point when Quin peeped around the kitchen door.

"Don't eat me," he said. "There's a knob in the fourth library."

Ariel considered the relative merits of smacking her brother vs. learning about the knob. The knob won out, but only because Quin was likely to stick around longer. She dusted flour off her hands. "Right. Show me."

There was indeed a doorknob in the fourth library. The brass curlicues were deeply worn, and hundreds of hands had filled the crevices with gunge. Someone had once jammed a stick in the keyhole, and it was still there, broken off flush with the fingerplate, which was gouged with scratches from someone's efforts to dig it out. The knob was set into the frame of the natural history bookshelf, which was now neatly remodeled to swing on nearly invisible hinges.

"Blast," Ariel said. "You brought me all this way to look at a jammed door?"

"Maybe it wasn't jammed shut," Quin said. "Maybe it was jammed open."

Ariel tried the knob. It wouldn't turn, but the door swung creakily into the room.

Inside, everything was deep green--green carpet, green dusty drapes, green wallpaper in a heavy, elaborate vine pattern. The furniture was old, heavy, and dark, polished but not too well, dusty but not too much, and the dim green light filtering through the drapes turned it black-green. There were a couple of fat green arm chairs by the green hearth, which was surmounted by a mantel covered with a green-fringed cloth, three dusty ceramic foo dogs (all green), and a bowl of ancient mints. Most of the rest of the furnishings were just bric-a-brac and Victorian room chum, but against the far wall was a massive secretary with faded green silk curtains.

"If there's anything interesting in here, it's in that desk," Quin said, and started forward. Ariel grabbed him by the waist and dragged him back.

"Don't," she whispered. "I think it's an arsenic room."