Elder Jarvis met Elder Shore, Tucker's Marseille companion, as Shore was leaving the mission field. Jarvis reflected in his journal, "Never have I met a man who more completely won my respect and confidence. My entire soul reached out for instruction and he imparted quite a bit to me concerning the wearing of the Priesthood garments and concerning the spiritual value of the Word of Wisdom." Jarvis was in Paris from January until August 1958, constantly exposed to Tucker and his adherents, and by that April he had become totally absorbed in the movement.

While Tucker taught the primacy of seeking the Spirit for guidance in conducting missionary work, he privately went out of bounds, encouraging the elders to discount the current Church leaders' teachings in favor of doctrines culled from sources such as the Journal of Discourses, a compilation of sermons by early Church authorities. He taught that some General Authorities lived polygamously in secret and that the Church proper had collectively apostatized from the principles on which it had been founded. He decried the unquestioning acceptance of tradition and urged immediate reformation. Jarvis commented in his journal: "The events of the next few years are going to try this church from the bottom to the top and I fear much persecution from the members of the church who are founded on tradition rather than real testimony."

Confronted by Tucker's beliefs, many elders now considered issues they had not encountered, much less resolved, before their missions. Elders with little Church experience were particularly susceptible to Tucker's visionary teachings. Caught up in his enthusiasm and conviction, they were perhaps unprepared to determine whether or not the spirit Tucker instilled in them was the true spirit of missionary work by which they should guide their own efforts. Missionaries also did not always realize that in considering Tucker's ideas they were courting apostasy. Marilyn Lamborn, the sister missionary who had first met Tucker in Geneva, later admitted: "I was just thrilled with my new knowledge. I'd write home and say these beautiful doors were being opened to me. I guess my letters must have sounded crazy. I really didn't think I would ever have to give up my beloved church. I didn't know I was headed in that direction."

Elder Tucker held great sway over the entire Paris corps of elders as well as many others throughout the mission. One estimate is that a third of the 130 missionaries in the French Mission eventually came to be in sympathy with Tucker. According to another source about thirty of the missionaries could have been considered firm believers. Under his influence, missionaries began to study rather than proselytize, and some began to wear only the "old style" temple garments.

Loftin Harvey, as yet unaffected by the Tucker faction and their teachings, was transferred to Marseille in the winter of 1957-58 just as Tucker was leaving for Herstal. It was in Marseille that Harvey first indirectly encountered Tucker's doctrines. Harvey was the senior companion of J. Bruce Wakeham, Tucker's California double who in spring would be appointed to join Tucker's Paris group as a traveling elder. That winter Harvey and Wakeham worked in Marseille with Elder Bob Johnson and his junior companion, Wayne Cheney. During a testimony meeting of the four elders and sisters Marilyn Lamborn and Wanda Scott, Cheney professed belief in the Adam-God theory, a doctrine no longer taught in the Church. Johnson, his senior companion, objected vehemently. Before the confrontation came to blows, as Harvey suspected it might, he took control of the situation, trading junior companions with Johnson until tempers settled.