The realtor called the staircase a "feature." It dropped past our new cellar, past a wine room nobody asked for, all the way down to a cold concrete floor. In Hollow Marsh, every house had one, each deeper than the last, like the town was competing. Our first night, Mrs. Edevane from next door knocked. "Whatever you do," she said, "don't go past the frost line."

I asked Mrs. Edevane what the frost line was. She pointed at my feet. "You'll feel it. The step where the air turns to ice. Below that, the house stops being yours." Then she left a thermos of soup and hurried home. I stood at the top of the stairs, looking down into the dark.

I skipped the stairs and ran to Mrs. Edevane's house instead. Her own staircase door stood open, breathing cold air into her kitchen. "Mine goes deeper than yours," she said, almost proud. "That's why they visit me first." Behind her, the stairs creaked. She smiled, stepped down toward the dark, and pulled the door shut after her. She never came back up. The next morning her house stood empty, and the cold from it had crept across our shared wall.