Kaitou Tenshi Twin Angel: Toki to Sekai no Meikyuu

Haruka and Aoi are a pair of friends who become the magical Twin Angels in order to fight off evil as the Red and Blue Angels. Their story revolves heavily around tracking down and protecting Seven Amulets; magical pieces of jewelry capable of generating immense power when assembled from a mysterious man known only as Black Trader and his subordinates. They are eventually joined by Kurumi the White Angel.