Dexter and Lumen first came into contact when Dexter killed the first member of the group with Lumen as a witness to the crime. After this Dexter explained that he saved her and she explained that he wasn't the only one who did that to her. Dexter and Lumen later went on their own quests for justice and ended up joining forces after Lumen found one and Dexter ended up killing him and another killer rapist he was already in the process of killing.