The three main characters from Næturvaktin, Georg Bjarnfreðarson (Jón Gnarr), Ólafur Ragnar (Pétur Jóhann Sigfússon) and Daníel (Jörundur Ragnarsson), have become imprisoned in the infamous Litla-Hraun prison following the murder of the hotel owner in Dagvaktin.
The name hraun comes from the Icelandic word for lava. The Hraunfossar are situated near Húsafell and Reykholt and lava-tube cave Víðgelmir is close by.