Witch on the Holy Night is a fantasy visual novel set in Type-Moon's "Nasuverse". The main story is completely linear, containing no branching routes or choices. It follows Aoko Aozaki, a high school student from the Aozaki family of mages, as she finds herself thrown into the world of magic after her grandfather appoints her as head of the family. She moves into an old mansion to be trained in the magical arts by young witch Alice Kuonji. When mysterious intruders appear to disrupt the magical field in their town, the two witches set out to discover their identities and motivations.
The gameplay is straightforward, with the player controlling Aoko or other characters as they navigate the story. The bonus chapter " Potete dormire, ma nessun rida " offers an additional layer of interactivity, where the player must select choices on-screen to solve a murder mystery while trapped in Alice's mansion.