A woman is on holiday in Cornwall when she is bitten by a mysterious snake. Although she doesn't die from the bite, she is transformed frequently into a monstrous half-woman, half-snake and takes her revenge on innocent victims.
Like several Hammers, this has a colonial theme with a misunderstanding in a far corner of the Empire brought home with horrific goings-on in rural England. Down in Cornwall, Jacqueline Pearce suffers under a curse, which turns her periodically into a striking, venomous snake-woman whose bite causes frothing death.
Pearce gives a haunting performance and has a moving death scene, while Willman a substitute for Peter Gushing is also interesting as the monster's tormented but repressed father, Dad's Army's John Laurie is the local loon. It makes a change for an animal bite not to lead to the emergence of a superhero, so the plot comes as a welcome diversion from most films of their ilk.
The Hammer horrors were very hit and miss, but The Reptile proves to be a success mostly thanks to Pearce who plays a most convincing lead and Wilmann who plays her domineering father. The effects remain as unconvincing as ever but that doesn't hold it back.