In a couple of weeks i'm going to try running a game of Hunter: The Vigil for the first time and thought that it'd be a good idea to run my basic plot and premise past the internet first to see what more experienced GMs think of it and foresee any potential plotholes or pitfalls with it.
Setting: Modern-day London
Core Premise: The players are all friends of a student at the University of London, she was the second victim of a serial killer who seems to be reenacted the Jack the Ripper murders. Angered by the lack of progress by the Police in tracking down the killer they decide on vigilante justice in attempt to bring the killer to justice.
The Twist: The Ripper's victims are all part of a secret cult that has been attempting to free their god (need a good name for it) and bring about its reign on earth. The London sewer system in addition to helping to keep London sanitary is also an immense mystical sigil designed by the Masons that keeps the beast bound beneath the earth.
The original Ripper murders were an incomplete series of ritual sacrifices, that if completed would have destroyed the beast. The cult attempted to summon the spirit of William Gull from the afterlife in order to torture him into revealing how the Masons bound their god and how they can free it. Unfortunately their ritual was faulty and the spirit broke free, possessed the body of one of their members and is now stalking and ritually murdering them in order to finish the grim work the original Ripper killings left incomplete.
My Situation: So far i've got the basics of the plotline down.
The players will investigate the scene of the third murder, find clues that lead them to the victims apartment, the cults front organisation (a club at the University of London) and eventually lead them to the cults headquarters.
From there i'm starting to get hazy, i'd like to have them confront the Ripper for the first time after they investigate the Cult's headquarters, probably violently when he comes for the next cultist. He'd then probably flee from the scene of the murder, not wanting to murder uninvolved by-standers, which would give the group the chance to chase or track him back to his lair, where they'd then be able to corner him and force an explanation out of him.
After that i'm not really certain what i should expect from the players or where the plot should naturally progress to, it gives the players a nice supernatural ethical dilemma, but having them joining sides with Jack the Ripper to murder mundane human beings sounds a bit too insane.
The biggest problem i'm facing here is that i'm not really certain what level of lethality is a good match for a group or 4 to 5 rookie mortal characters in a nWoD game, i want to create a Ripper who's tough and dangerous but not one who's capable of slaughtering the players without breaking a sweat.
Anybody who knows the system care to help me out. Any ideas or inspiration for plot hooks, twists or other stuff that i could throw into the mix to keep my players interested as well.