He is entirely alone. Just six or seven years old. In a tiny voice he says he’s called Moses.
For those who know their Bible stories, it is a name that might resonate.
Someone has left Moses here - at the dusty border crossing that separates the violence of South Sudan and the safety of Uganda - hoping he will survive.
Perhaps he is waiting for his parents to meet him. But he doesn’t know where they are, nor when, even if, they’ll come.
There are many like him. South Sudan is the world’s youngest country - and its young are suffering the most.
From ethnic violence that has killed an estimated 50,000 people, more than a million have fled abroad.
The UNHCR - alongside Ugandan authorities who are remarkably welcoming - now runs what in five short months has become the world’s second largest refugee camp.
Bidi Bidi is home to 270,000 people - and it seems each is a witness to some appalling barbarity.
Margaret, a nursery school teacher, told us soldiers killed many of her friends and neighbours when they attacked her village.
"They will shoot us using guns and even slaughtered us using their knives," she says.
"And even tied you on the tree and stayed there in the bush until you die, not eat anything."
Then there’s Robert, a driver with a Christian mission, who narrowly escaped a patrol as he too fled the country.
"We saw some killing. Actually dead people. They are just killed. Knifed. Really slaughtered. Some 18 boys were just murdered."
Or Lena, just 16 and traumatised by the deaths of her mother and father.
"It’s war and our parents die," she says simply. "We are many orphans here."
The fighting pits the dominating Dinka tribe of President Salva Kiir against rivals.
The United Nations is sufficiently concerned at the escalation of violence to warn of the potential for genocide.
And yet the UN Security Council failed to agree an arms embargo on the country.
The UK government has provided more than £100m in aid to South Sudan this year and British troops are due to bolster the UNMISS peacekeeping mission in the months ahead.
But by then, there might be little peace to keep.
This week Kiir's government has rejected additional African forces supposed to guarantee security around the capital.
"It’s a conflict and both sides are using civilians. We hear of villages being plundered and burned. We hear of rape. So yes these killings are really happening," says Nasir Abel Fernades, senior emergency co-ordinator for the UNHCR.
"Somehow the world has to put pressure on the two sides to make this stop."