Na otvoritvi retrospektive priznanega mariborskega slikarja Karola Korenike se zgodi umor.
Žrtev je umetnikov sin, morilsko orodje pa del razstavljene umetnine – granitna kocka. Ko nekaj dni za tem umre še en član družine, se inšpektor Vrenko znajde pred posebno težko nalogo.
At the opening of the retrospective of the renowned Maribor painter Karol Korenika, a murder occurs. The victim is the artist's son, and the murder weapon is part of the exhibited artwork – a granite cube. When another member of the family dies a few days later, Inspector Vrenk finds himself on a particularly difficult task.
