When Geumseong's phone rang on Christmas Eve 2020, he answered nervously.
The previous year he'd made the perilous journey to escape from North to South Korea, using an international underground network of safe houses and brokers.
Eventually his mother's voice came from the speaker: "Geumseong, Geumseong, can you see me?"
Eunhee could hardly get her words out through sobs as her teenage son clasped his hand to his mouth.
"Mum, I'm doing well and I'm not sick," Geumseong quickly reassured her. The relief at seeing his mother's face was overwhelming.
"So much time has passed," she replied. “I can hardly recognise you.”
Geumseong proudly announced he was now taller than his mother. He lifted his hair, showing his teenage acne to make her laugh
Then he picked up the phone and took her on a tour around his new home in the South Korean capital, Seoul.
"The house has three floors, it's really big!" exclaimed Geumseong. "It even has a piano."
"Wow!" his mum responded.
Until he was 15, Geumseong lived with his mother in a North Korean village near the Chinese border. He is guarded about the details of their lives and will only say it was extremely tough.
"When she did difficult work, I helped her. Sometimes when she was overwhelmed and exhausted, we cried together," he said. "That is how we lived."
It was a life the pair risked everything to escape.
The last time Geumseong saw his mother was in June 2019, on the banks of the Yalu River which separates China from North Korea.
It's a heavily fortified border. There are high fences on both sides that are often electrified, with guard posts every few hundred metres.
It was only once they had made it safely across the river together in neighbouring China that his mother revealed the sacrifice she had made.
Eunhee would be sold as a bride to a Chinese man, like tens of thousands of North Korean women desperate to escape their country have been since the 1990s.
In return, the broker who arranged the match would help Geumseong travel 4,000km (2,500 miles) through China to Thailand, through endless checkpoints, surveillance and security.
Over the decades, around 30,000 North Koreans have made the risky journey across the border and through China to South Korea in search of a better life.
If they are caught they face torture, forced labour in prison camps, sexual assault, and in some cases execution on their return, according to rights groups. For the North Korean regime, those who escape are considered enemies of the state.
Geumsong was horrified to discover he would be separated from his mother. But they had to part quickly before they were spotted by the North Korean and Chinese border guards on patrol.
After an arduous, nearly two-month long journey hiking through Thailand, Geumseong eventually made it to Seoul.
