Darker than Black - Kuro no Keiyakusha: Gaiden (OAV) [OVA]

After the incidents in Tokyo, Hei and Yin try to bury their past and start a new life, but everywhere they go someone seems to be following them. Unaware to Hei, Yin’s current odd behavior appears to be related to a prophecy that might lead to the end of the world.