Flanked by a heavily armed private security team, David Shearer is trudging around the labyrinth of makeshift huts at the Protection of Civilian Site 3. Guarded by the United Nations, the camp is home to more than 31,000 people displaced by war.
One of his staff helping with the tour eagerly informs him that the defensive tower they're about to inspect is "very robust". Once inside, Mr Shearer is shown three machine guns that have recently been installed against the mud-packed barricades.
White tanks with the signature black UN stamp sit idle against the razor-wire perimeter of the site.
From the tower, Mr Shearer looks out across the sea of white tents. The defenceless have sought shelter here. After being subjected to a campaign of killings, rape and fear, it's the only place they feel safe. There are stories of children being gunned down by soldiers, homes burnt to the ground and livelihoods lost.
It's a world away from his home in leafy Pt Chevalier, Auckland, but Mr Shearer, wearing army green chinos and a light blue shirt, looks like a man in charge. In his typically laid-back Kiwi way, he shakes hands and engages in small talk with some of the UN troops. He smiles and listens. But underneath the pleasantries, he knows the situation here is dire. Having worked in places like Iraq, Afghanistan and Kosovo in the past, he's no stranger to the world's most hostile environments. But Mr Shearer says the task he's faced with in South Sudan is one of the most challenging he's ever encountered.
The struggle for peace
Mr Shearer's in charge of around 14,000 peacekeeping troops and police officers. It's challenging because just deploying troops and getting supplies into most areas is a logistical nightmare. The roads are often impassable, there are military checkpoints everywhere, and fighting in some regions makes any form of travel too dangerous. Mr Shearer says the job can be isolating too.
"It's sort of lonely in a way, but that's just part and parcel of the job - particularly if you're the leader an organisation like this. As they say, it's lonely being at the top."
It's lonely because of the grinding demands of daily life, his nightly 7pm curfew, and the seemingly impossible task of facilitating peace in a land where war is entrenched. He's also a long way from his wife and children.
He returned home recently, but such trips don't happen regularly and he largely relies on Skype to catch up on life back in New Zealand.
South Sudan is in the midst of a bloody four-year civil war that's now produced the world's fastest growing refugee crisis. More than 1.5 million have fled to neighbouring countries and a further 1.6 million are internally displaced. Mr Shearer's job is to not only protect civilians and oversee the investigation of human rights abuses, but he's also trying to guide the country's leaders on a pathway to peace. That aspect of the job he says is "hugely challenging".
Multiple promises of ceasefires and peace agreements have failed. In fact, Mr Shearer says the violence has only worsened in recent weeks.
"There's now fighting on four different fronts across the country and outbreaks of sporadic violence in other places as well."
Mr Shearer says peace will only be achieved through a concerted effort from both sides to work together and lay down their arms.
"It's about trying to bring about a political settlement, not a military or violent one."
But that's incredibly hard when you're dealing with two political opponents who are both ex-soldiers. After years of war, negotiations here usually happen through the barrel of a gun. It feels a bit like the world's superpowers have given up on the basket case that is South Sudan. The guns and ammunition fuelling the misery come from eastern Europe and parts of the Middle East.
Despite some warning of genocide, a draft resolution to impose an arms embargo on the world's youngest nation failed last year after Russia, China and three African Council members - Angola, Egypt and Senegal - rejected the plan.
Mr Shearer has inherited the role as head of mission for the United Nations here at a time when confidence in the organisation has been severely shaken. In July last year in the capital Juba, a bloody three-day battle broke out between factions loyal to President Salva Kiir and those who support his former deputy Riek Machar. Ironically, both men had been in town for peace talks.
More than 300 people were killed and an investigation into the response by the UN was labelled "chaotic and ineffective". Multiple calls for help went unanswered, and on at least one occasion a woman was sexually assaulted in front of UN troops who ignored her screams and remained at their post. Staff from the World Food Programme requested protection at its compound, but no help arrived. When the fighting stopped, $41 million worth of food and equipment had been looted.
Mr Shearer accepts the UN response during this time was lacking. The peacekeepers are from 45 different nations and most are here on short-term contracts. They don't arrive in South Sudan wanting to fire their guns and kill. Mr Shearer wants to change the perception that the UN isn't willing to step up.
"I've insisted that our peacekeeping force be more robust over the last few months. We've had standoffs where weapons have been cocked and we've stood our ground."
He points to a recent attack on a UN base in Leer where the Ghanaian contingent fired back, protected the base, and successfully repelled the onslaught.
"I was really proud of them, and I told them that and I think they set the bar for the way I expect our peacekeepers to respond in the future."
In another case, Mongolian troops stopped fighters from abducting a group of young boys who were targeted to be turned into child soldiers. "[The Mongolians] would not stand down until those boys were released and I was very happy to know that all the boys were released."
The food crisis
Unity State in the north of South Sudan is in the grip of famine. It's the first famine announced in any part of the world for six years. Mr Shearer says it's a man-made disaster and it's easy to understand why. The ever-present threat of violence has led thousands to abandon their crops, their homes and in many cases their families. Fighting has cut off food supply routes, closed borders and put enormous pressure on humanitarian organisations. During our time travelling around South Sudan, I was shocked and saddened by the level of suffering.
At an emergency feeding site in Northern Bahr el Ghazal, the children arrived for screening frail and frightened. Dozens were weighed and measured as health workers documented the disaster in dust- filled scrapbooks. Plenty of hunger related deaths have already been recorded in this region, which is on the brink of being officially declared in famine.
The women arriving at the site look exhausted and desperate. Some have walked hours to get here in the harsh African heat. Cradling her daughter, mother Aweng Piol tells me: "I don't know whether it is disease or hunger, but my child keeps losing weight. I have nothing to give her and I'm really worried she might die."
Another woman, Bakhita Avuk, tells me the last time her two-year-old had anything to eat was yesterday morning. It was a meal of cooked leaves. Her eyes harden as she goes on to explain that she recently buried another of her children.
"The child was okay and then all of a sudden she had diarrhoea in the evening and in the morning she'd died."
The 300-odd children screened during our visit get a special high-nutrient powder. But as it's the only food families have, it often ends up being shared among many.
Even during monthly ration distributions, the need is overwhelming. Hundreds are registered to receive food including rye, sorghum and oil from World Vision through an innovative programme that requires beneficiaries to plant crops. But alongside those getting supplies are hundreds of people who are unregistered. They wait and hope they'll get help too, but most leave empty-handed. We saw little boys scrapping together beans that had spilled from aid sacks onto the dusty red earth.
Pressure on neighbouring nations
Across east Africa, almost 23 million are severely food insecure. Hundreds of people, mainly those fleeing war in South Sudan, arrive at Kakuma Refugee Camp in northern Kenya every week.
At the arrivals area I was approached by a man from Burundi who told me how he'd been tortured by the military there.
At a food distribution site within the camp, mother Ajulu O'Koce detailed how she'd been raped by soldiers in 2008 while trying to escape war in her homeland of Ethiopia. When her brother tried to find her attackers, he was shot. She's been here for 10 years and will never return to Ethiopia. She has no expectation that she'll ever leave Kakuma; no idea where in the world she'd like to live if she got the option. This is her home now and despite enduring such extreme suffering, she tells me at least she feels safe here.
The numbers pouring into places like Kenya has put huge pressure on a region that's already struggling with resources and in the grip of the worst drought in more than half a century. Farmers we met spoke of entire herds of animals dropping dead in the heat. The dry conditions are not only causing starvation and loss of livelihoods; it means farmers can't trade animals to pay for school fees for their children.
There is so much hardship for the people here, but I was astonished by their resilience and determination to carry on. Children still smile and joke when we meet them. They watch captivated by the sight of two tall white men sweating and lugging around piles of camera gear. A group of children push an old tyre around, and play a game of swing ball with an old plastic bottle. There are shrieks of laughter and there is still hope in this place of disaster and destitution.
Michael Morrah travelled to East Africa with assistance from World Vision. Click here to donate to the East Africa Hunger Crisis campaign.