Nocturnal Butterflies is the only film entirely made in Servaisgraphy, a technique that fuses live-action and animation. The late Raoul Servais, a key figure in the history of Belgian animation, already experimented with this style in his film Harpya.

After Nocturnal Butterflies, he stopped using Servaisgraphy, because the development of computer technology made the process virtually obsolete. It makes Nocturnal Butterflies a scarce, unique film. Based on the work of Paul Delvaux, a moth leads us into the waiting room of a night railway station, where a surreal sketch unfolds.