On a cold December morning the Penobscot steams under the Chamberlain Bridge and Brewer sits across the water like a photograph. Martin Property Maintenance works both banks — plowing and salting drives and lots through the dark half of the year, mowing, trimming and cleaning up yards through the green half. River air makes ice out of anything wet, so sand and salt do as much of the job as the blade does. Returning to a property twice inside one storm is ordinary here, not extraordinary. A walkway somebody can cross without thinking about it is the entire story.