Jonny's in the Slag caves. Find a way to get Jonny back home to Balthas

Speak with Jonny's father, then with (or without) the dog go to the Slag caves under the Ghost Farm and proceed to the very back with the children, by the underground reservoir. Jonny is the little boy that doesn't move(the dog will stand infront of him). He will ask you what his father's name is if he doesn't trust you and will tell you to go ask the leader of the Slags for premission to leave.

If you've made peace with the Slags and the Modoc residents, the Slags will escort you to Modoc and Balthas will reward you with a special type of armor.