That's because its 90,000 members worldwide have taken a vow of secrecy - and those who have left report persecution if they break that vow. Meanwhile, Opus Dei is working to become the most influential player in the Catholic Church. To this end, it maintains a secret network - including branches in Germany. 
It is no coincidence that the German headquarters are located in Cologne - Germany‘s most powerful Catholic archdiocese. In Germany, Opus Dei is focused on trying to gain a foothold in the field of education, by running daycare centers and schools.
The examination of a daycare center in Munich shows that Opus Dei deliberately conceals its involvement in these institutions. Another component of the network is IESE, the business school of Opus Dei, which also has an offshoot in Germany. It is considered one of the best schools of its kind in the world.
In Spain, where Opus Dei originated, sect members are active in parts of the judicial and educational sectors. The documentary tries to uncover these connections in both Spain and Germany, and lets both victims and experts have their say. It also includes an interview with the head of Opus Dei, Christoph Bockamp.
For the first time, a former member from Germany reports on her ordeal in Opus Dei and the harassment she experienced after she broke away from the sect. Spaniard Carmen Charo developed mental health problems during her time in Opus Dei, due to brainwashing and psychological pressure. Today, she helps others in their journey out of Opus Dei.
Dietmar Scharmitzer is trying to do the same thing with German-speaking people who want to leave, and runs an Internet platform to help inform them. Finally, Marco Politi, an author and Vatican expert from Rome, takes stock of the influence Opus Dei has exerted since the time of Pope John Paul II.