Description
In the 20th century in the fictional village of Clagmoor Heath in Cornwall several locals are dying from what is deemed to be the "Black Death". Harry Spalding inherits his late brother Charles' cottage and arrives with his new bride, Valerie. The inhabitants of the village keep clear of the newly arrived couple and only the publican, Tom Bailey, befriends them. Tom explains that the hostility exhibited by the townspeople is the result of many mysterious deaths in the community.
The sinister Dr. Franklyn, the owner of the nearby Well House, is the only resident in the vicinity of the cottage and he lives with his daughter Anna. Franklyn treats Anna with cruel contempt and she is attended by a silent Malay servant.
Hoping to learn something of the deaths, Harry invites the local eccentric, Mad Peter, home for dinner. After warning them that their lives are in danger, Peter quickly departs only to return later that evening with his face blackened and swollen before dying. The Spaldings attempt to alert Franklyn, but he arrogantly states that Peter's death is not his concern, explaining that he is a Doctor of Divinity, not a surgeon.
In an attempt to help Harry clear up the mystery, Tom illegally unearths Peter's corpse and discovers a strange neck wound like a snake bite. Harry and Tom dig up Charles’ coffin and find that his corpse also has those same marks. Realizing that they are threatened by something far worse than they had ever imagined, Harry is quick to answer an urgent message from the Well House. There, he is bitten by a mysterious reptilian creature, but he still manages to return to his home and recover from the bite.
Meanwhile, at the Well House, Valerie witnesses Franklyn's attempt to kill Anna, who was changed into the reptile creature after being abducted and cursed by a Malay snake cult that included the Malay servant. A struggle ensues between Franklyn and the Malay, accidentally causing a lantern to be knocked over and setting the house ablaze, killing the Malay. Franklyn is bitten by Anna and dies from the bite. Anna attempts to bite Valerie too, but dies in the fire. Harry and Tom arrive and save Valerie. The three escape safely and watch as the house is consumed by the flames.
