The film tells how a journey to South America inspired Che Guevara's new worldview and made the revolutionary enthusiasm begin to sprout in his heart. Guevara (Gael García Bernal) was 23 years old, full of vigor and hesitation, and was a medical student. He had a strong curiosity about the outside world, so he and his friend Albert embarked on a long journey in Latin America. They rode on a motorcycle and set off at a speed, but unexpectedly the motorcycle was soon scrapped. But this did not affect the passion of the young people at all, and the two relied on hitchhiking to complete the rest of the journey. Passing through the ancient civilization sites of Latin America and shuttling among people of all colors in various countries, they began to truly feel the truth of society and the suffering of life. When they went deep into the leprosy area in the Amazon River Basin, they were deeply shocked by what they saw and heard. Che Guevara began to think about the grand and profound propositions: human beings, society, economy, civilization, human suffering, the definition of happiness...