The film covers the period from 1939 to 1963 and reveals the circumstances of the arrest, imprisonment and release of Josyf Slipyj, which are not known to the general public.

The film pays special attention to historical events and prominent personalities of that period and their influence on the fate of Patriarch Josyf Slipyj. The film's protagonists are Pope John XXIII, US President John F. Kennedy, and General Secretaries of the CPSU Central Committee Joseph Stalin and Nikita Khrushchev.

The title of the film was inspired by the Reefs intelligence file, which is kept in the archives of the Security Service of Ukraine. The 33 volumes of the case document in detail how the Soviet authorities developed and implemented a plan to destroy the Ukrainian Greek Catholic Church and its head, Josyf Slipyj. These documents, which were carefully collected and stored by the Soviet repressive system, became the basis of the film.

The film includes testimonies of participants and eyewitnesses of the events, comments by historians from Ukraine, Italy, and the United States, and unique newsreel footage that the film crew found in Ukrainian and foreign film archives.