Andrew Graham-Dixon opens his three-part series on Christian art with the moment classical art starts to disappear and something stranger takes its place. He traces the shift through the declining Roman Empire, where painted portraits of the dead still cling to naturalistic detail, into Egypt, where those same traditions curdle into the flat, staring faces of the earliest icons. The film treats this as a deliberate break rather than a decline in skill: artists abandoning realism because a physical likeness stopped being the point, and a symbol of the eternal soul became more important than an accurate face. Graham-Dixon carries the argument into medieval France, reading church art as an attempt to make heaven visible on stone and glass rather than merely illustrate it. Mosaics, early panel paintings, and church architecture appear throughout as evidence, with Graham-Dixon narrating on location at the sites where this art still survives. The episode's real subject is a single question: what does it look like when painters stop trying to show the world as it is and start trying to show the world as it should be, eternally.