Lost Fortress invites players into the eerie halls of Tamloth Fortress, an ancient castle steeped in mystery and long-lost grandeur. Set in 1846, the story begins with young playwright Alex Stone, who arrives at the fortress seeking inspiration. Once home to the enigmatic Chronis family, the fortress has become a place of whispered legends and forgotten tales, abandoned without explanation.

As players explore the decaying rooms and labyrinthine passages, they uncover fragmented records, strange symbols, and hidden clues revealing the family's tragic descent. The journey involves solving intricate puzzles, piecing together the family’s history, and deciphering ancient and powerful ituals tied to celestial alignments. By unraveling the secrets of the fortress, players may find themselves entangled in forces that transcend time itself.