Nearly two decades later, that question still stays with Vi, co-CEO of Blue Dragon Children's Foundation, which rescues vulnerable children in Vietnam.

Once a homeless shoe shiner himself, Vi joined the organization planning to stay for only six months. But he never left because of one unwavering belief: "If it is not me either, who will believe these children?"

In an interview with VnExpress, Vi speaks about rescuing children, the lives he could not save, the psychological scars that come with his work, and why he still cannot walk away from a job he hopes one day will no longer exist.

Q: What changed your life and led you to help street children?

I used to live on the streets of Hanoi, earning money by shining shoes. My family was poor, so I ran away to the city with a few friends.