Two hundred years after a mysterious gas turned most of humanity into horrifying immortal creatures, the world has finally rebuilt itself. The infected were supposedly wiped out long ago... except for one place: Blackthorn Manor, a sealed estate hidden deep within a dead forest where something inside still moves.

Every night, screams echo from the manor halls.

No heartbeats have ever been detected inside.

When young scientist Mai Tanaka volunteers to enter the cursed estate with hidden cameras and live surveillance, she expects monsters.

What she finds instead is far worse.

Inside the decaying manor, the infected Blackthorn family still lives trapped in a twisted version of the 18th century — the terrifying master Abel Blackthorn, the unstable yet elegant Hilda Blackthorn, the obsessively possessive heir Charles Blackthorn... and you, the silent young lady who has watched the world decay for centuries.