Two years ago, FT journalist Antonia Cundy began investigating the controversial Catholic organisation Opus Dei. The story she uncovered was not what she expected. Because what started as an investigation into the impact Opus Dei had on individuals turned into an account about how it is changing a country - the United States - and its culture. There, despite having only 3,000 members, Opus Dei has developed significant connections to power.

In this series, Antonia hears from former members who joined Opus Dei to deepen their faith but said they found unstated agendas – and unexpected harm – entangled in that spiritual mission. They share stories of opaque attempts to wield influence, and a drive to expand that came at the expense of people’s freedom.

From small towns to Ivy League universities and Washington’s corridors of power, Antonia unpicks the reality of this often sensationalised group and uncovers how its culture, practices and worldview have led it to become a central pillar in an ascendant conservative movement.

The series raises questions about intentions and their consequences: when does guidance become control? When does privacy become secrecy? And when does spiritual belief become political ideology?