This mission unlocks after you take over the outpost Road assistance Welshore building.
In Amanaki, talk to the parents of a missing girl. Exit the village on the south side and drive towards the area pointed to. You will find a corpse and five monitor lizards here, shown in the screenshot, which need to be killed in order to secure the area.
Jif you retreat a bit, to the nearby hillock, the animals will have problems attacking you.
Once you dispose of all of the monitors, approach the girl standing on the rocks near the corpse. After you listen to her story, the mission will be over.