Elijah travelled from the Silver Shadow pack to the Dark Howl pack, searching for any news of the non-shifter. They had first gone to the Silver Shadow pack and realised that she wasn't there. When they asked the alpha, they were told that they hadn't taken in any rogues for the past three months.
So he was almost certain that she must have sought refuge from the other neighbouring pack if she wasn't already devoured by a hungry wild animal. They called the Dark Howl pack to enter their territory, stating that they were paying them a short visit to look around. It was not abnormal for wolves of other packs to visit from time to time, especially if they were young.
Some of them often travelled to look for their mates if they couldn't find their other halves in their packs. So Miles didn'
