Witch Hunter Robin

To Michael's chagrin, a hacker has broken through his defenses and entered the STN-J's systems; a Witch's symbol is being broadcast from Robin's terminal. Meanwhile, Robin had spent the night talking to the mysterious old woman she met in the Walled City. Is she a 'Methuselah', a Witch rumored to be immortal? And will Robin be able to accept what she is telling her?