Moses has the saddest eyes. Big and pained and close to tears.
He is lost and alone. An only son of a missing mother he must presume dead. In his dreams, she speaks to him.
"She says she is sorry for leaving me alone. She says only God will be your sponsor now."
I ask Moses whether thinks he will ever see her again in this life.
"That I don’t know. There was so much shooting," he says.
Moses, just 15, tells me a story I hear time and again from similarly forlorn children.
It starts with soldiers coming to his village, continues with them killing and burning, and ends with him running in panic and without his mother, lost in the confusion.
UNICEF works hard here to reunite children with missing parents.
Sometimes there’s good news. Much more often there’s not, says Anna Hadjixiros, UNICEF’s child protection officer.
"For many of them, unfortunately, it will be bad news. Because from all the accounts we hear, many families, many parents, many fathers and mothers are killed, but many of the children are aware just yet."
Moses is among thousands who have taken shelter in a school in the town of Yambio, in the south of the country.
Last month saw fierce skirmishes between government forces and rebel militia in the countryside round about.
The fighting has left mile after mile of deserted and burnt out villages by which you can measure South Sudan’s descent from world’s newest nation to failed state.
In Yambio, there are around 150 soldiers of the UNMISS force tasked with protecting civilians.
We watch a patrol set out. Grim faces, anxious expressions. Lightly equipped. Far too few to effectively police such an enormous area.
Major Dave Leonard, a New Zealander with the United Nations force doesn’t deny the impossible odds.
But he insists: "I really believe we are making a difference here. Providing oversight. If weren't here then it would be worse. Even more bloodshed."
Britain’s forces due to bolster UNMISS won’t be stationed anywhere near here. Rather they’ll be far to the north.
But you see why some have called the deployment of a few hundred engineers a sticking plaster to cover a gaping wound.
South Sudan's decline has taken little more than five years.
It is an object lesson in the limits of the west’s ability to nation-build, for a country enthusiastically supported – financially and diplomatically - by the US and Britain has been brought to its knees by corruption, high level criminality and murderous tribal divisions which were all, in hindsight, easy to predict.
For now, around Yambio a fragile and tense truce is holding between pro government and rebel forces. But no one believes it will be long before the killing starts again.
We meet Moses a second time, pushing his bike along the road out of town.
He says he’s in search of something to eat. Maybe too he hopes to track down his mother. But those sad eyes don’t hold out much hope.