After you finish Heap of Trouble, speak with Kaeluf to learn that two hunters are likely lost now due to him switching duties with one of them. You can optionally talk with Petra after Kaeluf, if you want, then it's time to go and track down these hunters. Kaeluf mentioned they were northwest of Free Heap and if you look at your map with the quest active, you see they are pretty far from the village. Fast travel to a nearby campfire and when you get close enough, you should hear the two hunters arguing by a large stone arch.
Kaeluf's suspicious are confirmed, as the pair lost the herd of Behemoths. You have a choice here of whether to bring them along or not and considering you'll be fighting a lot of machines at once, having them as distractions won't hurt. From the arch, use your Focus to find the tracks, going southeast to find the Behemoths. There are three of these things, along with three Shell-Walkers escorting them. You need a total of nine cables and guess what, each Behemoth drops three of them, so you'll need to kill them all.
Before you're seen, a good tactic is to use a freeze arrow to hit one of the Behemoth's Freeze Canisters, preferably one in the middle to spread the freeze explosion over more enemies. While they're frozen, you should use that chance to inflict as much damage as possible to them to try and quickly reduce some of their numbers. Things will be hectic a bit, so if any of the machines run away, let them go to get a slight breather. Once you've killed them all, loot the cables. If the hunters joined you, talk to them to be given a choice to either hand them the cables or bring them to Petra yourself. If you did this solo, return to Petra to finish the quest.
|For retrieving both the lost hunters and Behemoth Cables||5,000 XP / +1 Generous Reward Box|