What did the House of Mary in Nazareth look like?... Are the walls we find in Loreto truly those of the House of the Annunciation, which took place more than 2,000 years ago? For many centuries, scholars from many disciplines have investigated the authenticity of the three walls venerated in Loreto. Initially, researchers analyzed numerous documents held in archives throughout Italy. The twentieth century also saw archaeological, geological and architectural studies. According to legend and tradition, the house was carried in flight by Angels in the year 1291, first to a town in Croatia where it remained for three years before being carried yet again, across the Adriatic Sea to Italy, and then to its present location in Loreto. This is known as the Miracle of the Translation. Modern academics have theorized that it was moved by Christian soldiers fleeing the Holy Land near the end of the Crusades. The entire journey of the Holy House was re-created for this documentary film, with the help of state-of-the-art 3D computer-generated graphics. The Holy House does not rest upon typical structural foundations, and its presence in Loreto remains a real enigma for contemporary architects. It is formed of three simple stone walls, dark with smoke and time, only lit by candles. Inside there is an ancient altar, known as the Altar of the Apostles, and an aperture in the western wall, called the Angel's Window marks the point at which the Archangel Gabriel entered the House and appeared to Mary, in the Annunciation. Is this sacred structure really the very same House of Mary, transported all the way from Nazareth? Are these simple, unadorned stone walls in Loreto truly those of the House of the Annunciation, which took place more than 2,000 years ago? Loreto: The Mystery of The Holy House gathers all of the available evidence to find the answers.