Final answer:
After Runt tracked Pax and Bristle to the river, he got scared by a rabbit and ran away, getting lost in the forest. He wandered for an hour before falling asleep near a stream.
Step-by-step explanation:
Runt tracked Pax and Bristle to the river, where he encountered a rabbit. Frightened, Runt ran away and got lost in the forest. He wandered for an hour before finally falling asleep near a stream. Meanwhile, back at the plantation, Runt's mother was heartbroken over his disappearance.