The Watering Hole is the place where animals drink and it is also the place where the Great Gathering is held. It was also the place where Great Mother was murdered. Stinger Crownleaf declared himself as the Great Father at the Watering Hole and also blamed Thorn for his horrendous acts, in front of all the other animals.
After Thorn proves his innocence, he alongside Sky and a repentant Fearless, go to war against Stinger.