It was one of the great crimes of the Second World War: from 1941 to 1944, a total of 872 days, the siege and starvation of Leningrad by the German Wehrmacht on Hitler's orders lasted. Over a million people fell victim to the blockade, most of them dying of hunger. Countless of these starving people wrote diaries with the last of their strength, and cameramen filmed in the paralyzed city. Evidence from the hell of the siege, many of the film recordings, but above all the written memories on which this documentary on the occasion of the 80th anniversary of the liberation is based, remained under lock and key after the war. The voices of those who had suffered through this terrible time should not be heard by anyone, because they did not fit the pathos of the Leningrad heroic song that was officially sung. Most of the recordings come from women. The writers feared neither the enemy nor the Communist Party or Stalin, who often proved incompetent in providing for the population.

The Irish musician Oisín (Tadgh Murphy) and his band come to Berlin for a few gigs. They are excited about the city and its legendary nightlife. As they unpack their things at the hostel, Oisín finds an envelope with money from his father in his pocket. Later, at their concert, everything seems to be going well - the boys are in a good mood, the audience is going along - when Oisín suddenly freaks out in the middle of the stage. The anger at his father for abandoning the family and the pain over his mother's death overwhelm him and he throws himself into Berlin's nightlife alone. When he meets the young, pretty Berliner Sabine (Aylin Tezel) and she shows him places far away from the party and tourist hotspots, he seems to find support with her.

Garbage manager Rüdiger Dorn wants to move into his parents' house after the death of his mother - but that has to be brought into shape first. It goes without saying that Werner pitches in.

Water pipe burst and bomb alarm - Berlin in a state of emergency: Dorn and Gerald don't know where their heads are. The routes for the garbage collectors have to be reworked due to numerous road closures, chaos rages.

Music teacher Carlo, an easygoing old rock'n'roller, meets doctor Ellen in hospital. She is completely stressed out, so that even son Franz often falls by the wayside. A short time later, Carlo makes an unforgivable mistake: fed up with the pupils' never-ending paltry questions, he advises Franz, whose anger at his mother is slowly boiling over, that he should simply report her to the Youth Welfare Office.

Der Sandmann investigates the intersection of history and memory as witnessed against the backdrop of post–Cold War Germany.