This unaired side episode of Darker than Black sends the Contractor known as Hei and his teammate Mao on a Syndicate assignment: recover the belongings of a dead Contractor said to be buried beneath a cherry tree. The job pulls in a numbered vial and a rival Contractor, and a civilian named Mayu Otsuka ends up caught at the scene. Released on home video as a bonus episode, it slots beside the first television series rather than continuing it.