Alejandro Cruz still couldn’t understand how it happened so suddenly. One moment, his four-year-old triplets were under their nanny’s supervision in a busy plaza in Barcelona. The next, they were running—running—straight toward a stranger sitting on the sidewalk.

The girls—Isabella Marín, Lucía Marín, and Renata Marín—diagnosed blind from birth, moved in a perfect line through the crowd, avoiding people and obstacles as if sighted. Their matching dresses fluttered as they ran with purpose toward the gray-haired woman who opened her arms instinctively.

“Girls, stop right now!” cried Elena Torres, the head nanny, panic rising as control slipped away.

Alejandro looked up from his phone and felt his heart seize. His daughters, who usually needed canes and guidance, were moving with confidence he had never seen.

“Abuela… Abuela!” the girls shouted together.

The word rooted him in place.

The woman wore worn clothes and a faded shawl. Her hands trembled as she hugged the children with a familiarity that shattered Alejandro’s composure.

“Step away from them,” he ordered sharply.

But the girls clung tighter.