© 2019 The Authors. Data retention saga - Interpretative strategy of the Court of Justice - Expansive potential of the principles set by the Court of Justice - 'Reverse' effet utile and conflict of competence - EU acts under threat - Domino effect on national security measures - Future scenarios - Twilight of the model of bulk data retention - Modulation of the ban on bulk data retention according to the vulnerability of data processing or depending on the prior unknowability of the threats - Divergence from the European Court of Human Rights - Legitimisation of bulk data retention.