Worm Evolved

Hybridizing venomous snakes is a terrible idea. Mixing them with a destructive entity older than memory is an even worse idea. 

A series of murders in post World War Three England are linked to a venomous reptile. This animal, however, is like nothing ever seen before, seeming to combine the venoms of some of the most lethal snakes on the planet. 

Something, or someone, is setting this creature on people, with deadly effect.

A novice police officer and the members of an exotic animal rescue must discern the common thread between the ones targeted by the snake's handler. Matters are complicated when the venom appears to be getting more complex with each kill.

Something, or someone, is developing a biological weapon, one that might not be entirely natural. It is only a matter of time before the police officer and the rescue volunteers find themselves in the crosshairs, because the rescue is already harboring a secret. 

What could a small, slight teenage girl have in common with a chimeric serpent? And what, if anything do events of this day have in common with a haunted Irish castle two centuries prior?

Taipan Image: By AllenMcC. - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4442037