在那阴森的山谷中，魔鬼之足静静伫立，仿佛隐藏着无尽的秘密。主人惩罚奴坐冰块

　　Whilst in Cornwall Holmes is approached by the local vicar to determine how Brenda Tregennis died whilst sitting in a room, playing cards with her two brothers, who were struck down with dementia as a result. The trail leads to an African adventurer and a deadly root known as the Devil's Foot.