In Sasha Vesna’s apartment, Robert Langdon paces anxiously after finding a handwritten note slid under the door: “I have Katherine. Come to Petřín Tower.” The message convinces Langdon that Katherine Solomon is alive but in immediate danger, and he fixates on the ominous choice of the wooded hilltop tower.

Sasha fears they were followed to her home and wonders if ÚZSI is involved, but Langdon rejects the idea that Czech intelligence would kidnap Katherine. Unable to wait for Michael Harris to arrive and advise them, Langdon decides to leave at once for Petřín Tower.

Langdon orders Sasha to stay behind, meet Michael, and go to the U.S. embassy to report everything: Brigita Gessner’s death, the ÚZSI agent, the threatening note, and Langdon’s plan to go to the tower. Sasha offers Pavel’s gun for Langdon’s protection, but he refuses to carry a stolen weapon through Prague and instructs Sasha to hide it in her kitchen.

Instead, Sasha gives Langdon her spare apartment key on a “Krazy Kitten” key ring, so Langdon and Katherine will have access to a potential safe place if needed. As Langdon prepares to leave, he reveals he has Michael’s private number memorized from seeing Sasha dial it, prompting a brief exchange about Langdon’s strong memory and Sasha’s memory gaps caused by epilepsy. Sasha credits Brigita for helping her, and Langdon comforts Sasha as he heads out toward Petřín Tower.