The golem nods. "We'll just keep on movin', then," she says amiably. "Not like we can't stop there coming back."

The train pulls to a halt at Forty-Second, and the sound of steel drums fills the air: there's a man on the subway platform playing "Oh Little Town Of Bethlehem", and selling CDs of his performances. He's got precious little space to maneuver in. This is one popular station at this time of year.