The narrative thread of the series "One August Night" unfolds from the murder of Anna Petraki (Evgenia Dimitropoulou) by her husband Andreas Vandoulakis (Yannis Stankoglou), one night in August, six years ago, when the latter learns that she had a lover, his cousin Manolis Vandoulakis (Yorgos Karamihos).
The main role in the series is played by Anna's sister, Maria Petraki (Youlika Skafida), who tries to continue her life, keeping well-hidden secrets that must not come to the surface...

August 25, 1963. Six years have passed since the murder of Anna Vandoulaki. Her husband and killer, Andreas, is in prison with a life sentence. No one has visited him all these years.No one, except a new visitor who is now coming to find him - for unknown reasons. At the same time, in Piraeus, a mysterious man, with an unknown past, does everything he can to get his hands on a woman's lost earring. It's Manolis, Andreas’ cousin. And the earring once belonged to Anna. Anna loved Manolis and died for his sake.