This is an autobiographical account of the author's adventures in going as an evangelist to the Yuqui Indians of Bolivia. Reading that five missionaries had been killed by stone-age Indians in Bolivia, he felt called to take up the work they had initiated. Six years later a plane landed him, with his wife and two small children in the hot upland desert of Bolivia, at a time of civil war in the country. In the strange and dangerous events that follow, other missionaries join in the venture of bringing Christianity to the primitive tribes. The story is told in a popular tone, mingling anecdote and detail with allusions to the Gospel motive that inspires the ventures.