An hour later, Barnaby sang a cheerful little chime and docked himself back at his station. Sarah walked across the hardwood in her bare feet. There wasn't a single grain of grit or a stray pet hair to be found. For the first time in years, the floors felt truly smooth.

He navigated the maze of chair legs like a professional. He dipped under the bed, emerging with a long-lost earring and three months' worth of lint. He even managed to dodge the cat, who watched from the top of the bookshelf with deep, silent judgment.

When the box arrived, she unboxed it with the kind of reverence usually reserved for expensive jewelry. She named him "Barnaby." After a quick charge, she tapped the "Clean" button on her phone and watched with a mix of skepticism and hope.