Mark visit's Christian B's box factory where 8000 child abuse files were found, but discovers worrying weaknesses in the phone evidence linking Christian B to Madeleine's disappearance, and the credibility of a key German witness.

Christian B gives Mark a possible alibi and reveals his claimed movements the week of Madeleine's disappearance. Mark tracks his alibi down and speaks to her now partner. He tests the prosecutor's evidence further and reaches his series conclusion.