The Russian invasion of Ukraine in 2022, described by Chancellor Olaf Scholz as a Zeitenwende (turning point) triggered a fundamental rethinking of German foreign, security, and defence policy. This article conceptualises the invasion as a temporal shock to Germany’s ontological security. Building on the ‘temporal turn’ in International Relations, we argue that the war not only violated Ukraine’s national sovereignty and territorial integrity, but it also disrupted a broader sense of chronological continuity in European security, long defined by reduced defence spending and the assumption that interstate war was obsolete. Where previous studies have focused on the interrelationship of ontological security and temporality built around the concepts of biographical continuity, collective memory, and mnemonical security, this paper focuses instead on narrative disruption and the retiming of national security and identity via the perception of external shocks. We contend that the Zeitenwende narrative challenged historical concepts of German ontological security, such as Ostpolitik and Wandel durch Handel, that were deeply embedded in a strategic culture of military reticence by calling for the revitalisation of German military power. Yet this retiming remains constrained by incremental policy implementation and historical associations with Germany’s militaristic past, creating ongoing ontological insecurity about Germany’s role in European security.