In the 13th installment of the Untersberg series, Wolf embarks on a time travel journey into the Führersperrbezirk, from which he returns with many gaps in his memory. What information has he received that must remain a secret? Meanwhile, the Alchemist leaves him a mysterious clock that has fantastic abilities - and ultimately disappears without a trace. Together with Claudia, Wolf travels to Venice, where they follow in the footsteps of the Ordo Bucintoro. Meanwhile, mysterious events are piling up at the Untersberg, ranging from a radio message from the future to unexplained flight maneuvers, and even the appearance of a bicycle with propulsion technology that is still unknown.