The island's owner, Mr Vontin, and his forthright daughter Madeleine disagree, suspecting the invaders to be frauds, and take measures to have them removed. Andrew Doig, a well-bred and confident university student proud of his moral integrity and intent on pursuing truth at all costs, finds himself embroiled in a passionate debate over his defence of the inhabitants of St Sollas, a debate that is further complicated by the allegiance expected by his Uncle, who happens to be the Sheriff in charge of the eviction, and by his uncomfortable attraction to the cold-hearted but bewitching Madeleine. The Missionaries follows Andrew, The Sheriff and the accompanying police officers to St Sollas as the situation comes to a climax. An inspired study of human nature, the novel charts a voyage of self-discovery for Andrew as he is offered an easy route into aristocracy and wealth but is reluctant to relinquish his higher moral ground and it raises questions about attitudes towards social standing, moral righteousness and the Christian faith that are pertinent to this day.