While driving toward Threshold, Ambassador Heide Nagel receives an unexpected call on her supposedly unknown personal phone from Sergeant Scott Kerble, her Marine security lead. Kerble says he tried her other numbers and is waiting at the embassy because he has something urgent for her.

Kerble explains he found a sealed envelope lying on the corpse of Michael Harris and believes the killer left it to be discovered. The envelope is marked “Private and Personal” and is addressed specifically to Nagel, alarming her enough that she abruptly pulls the SUV off the road near the Winged Lion Memorial and steps out to take the call privately.

Kerble presses Nagel to come in immediately and uses a coded “errands” prompt that signals serious danger. Nagel avoids triggering a full security response by promising to return to the embassy within ten minutes and ordering Kerble to bring the letter to her office.

Nagel returns to Robert Langdon and Katherine Solomon and explains that if she fails to return promptly, her entire Marine detail will begin searching Prague. Realizing she cannot bring them near the embassy, Nagel gives Langdon her car keys and tells them they will be safer without her.

Nagel confirms there is no news on Sasha yet but promises to ask her tech officer for a facial-recognition sweep. She also warns that the old Samsung phone now seems compromised and that photos would be easy for the CIA to dismiss as AI fakes; she urges them to find documents or other hard evidence instead.

Langdon raises another risk: he promised his editor, Jonas Faukman, a call, and if Langdon goes silent Faukman may alert Prague authorities. Because Faukman will not trust a message from Nagel, Langdon writes down Faukman’s email and a strange, nonsensical message, insisting Nagel send it because Faukman will understand it.