"Just for a spot of wild Dementor catching," Narcissa replied bluntly. She rolled up her sleeve. The tattoo of a coiling serpent was moving on her arm, roiling and slithering angrily. "The Mark always burns when Voldemort is issuing orders to round up dissidents and others on his watch-lists. The Dementors will be swarming all over the country. I'll use the cover to nab you a test subject in no time."