The heart—while a marvel of engineering unlike anything else that had been created—sometimes needed more than metal or wiring to function: a drop of blood, pressed against the white strip above the gears. It did not happen often—at most, once a year, but Nurse Ratched never failed to remind them that according to lore, a creature known as a vampire subsisted on the same thing. The last time had been four months before, when Dad had started acting more robotic, more like a machine.
