Orphaned in infancy, Nicolás Téllez is raised by his grandfather Pedro in a rural Flanders village. The pair eke out a living delivering milk to nearby Antwerp by cart. On one journey, they discover a gravely injured dog discarded by the roadside. Nicolás refuses to leave it, nursing the animal back to health and naming it Patrasche. The dog becomes his devoted companion, sharing the milk route and their daily existence.

Nicolás displays artistic talent early, frequently sketching the natural world and village scenes. He idolizes the painter Peter Paul Rubens, aspiring to such mastery. His passion meets skepticism from villagers who deem it impractical. Only his friend Marta offers encouragement, valuing his drawings and requesting artwork during her illnesses. Their friendship faces opposition from Marta's father, who forbids contact due to Nicolás's poverty.

As Pedro ages and weakens, eventually passing away, Nicolás shoulders greater burdens. Wrongfully blamed for a village fire, his isolation deepens. His last hope emerges through an Antwerp art competition promising prize money and acclaim. Though his entry impresses the judges, victory eludes him. This defeat, coupled with his grandfather's death, leaves him destitute and without shelter.

With only Patrasche beside him, Nicolás endures the bitter cold, searching for refuge. In his final moments, he finds solace gazing upon a Rubens painting within Antwerp's cathedral. He and Patrasche perish together in the snow, reunited at last with Pedro and his mother.