It seems that Bishop Aringarosa (ALFRED MOLINA) called the agent, informing him that Robert was the murderer, when the real culprit was an albino monk by the name of Silas (PAUL BETTANY) who’s been killing off guardians of a secret society under orders from a nebulous party known as "the teacher." Managing to elude Bezu and his men, Robert and Sophie find several clues left for them near the victim’s body that lead to even more scattered about the museum.
That eventually leads them to Robert’s former associate, Holy Grail historian Sir Leigh Teabing (IAN McKELLEN) who believes their findings reinforce his belief that Christ was not a deity, but rather a mere mortal who fathered a child with Mary Magdalene. He goes on to say that a secret society has existed for several millennia whose sole purpose is protecting their descendents, all as the Church has covered up that fact through lies and murder.
Robert and Sophie are skeptical of such wild-sounding allegations that include Leigh’s unusual belief that the Holy Grail is not the chalice from the Last Supper, but rather Mary Magdalene. Even so, they realize various forces are intent on finding the Grail and thus set out to get to the bottom of this mystery, all while trying to avoid Bezu, Silas and others who are after them and the knowledge and evidence they’re collecting along the way.