Mary Skelter: Nightmares is a dark fantasy RPG that follows the story of Mary, a young girl who is held captive by a group of demons known as the "Devil Children". The demons, led by the enigmatic and sinister leader, Arachne, have taken over the town of Mary's hometown, and it's up to Mary to escape and defeat them. Along the way, she must form alliances with other characters, uncover the secrets behind her past, and confront the darkness within herself.
The gameplay in Mary Skelter: Nightmares is a mix of exploration, turn-based combat, and social simulation. Players control Mary as she navigates through dungeons, fighting against hordes of enemies and collecting items and equipment to aid her on her quest. The game also features a social simulation aspect, where players can build relationships with other characters and engage in conversations that affect the story and gameplay.