Frankenstein; Lost Souls: Dean Koontz

In this book a small town in Montana is taken over by one man's creation. Their goal is to get rid of all humanity and replace them with these "Alien" beings. The story gets to the climax and then just abruptly ends :( The beings are able to be killed, but they are much stronger than a human. The book sets a few people up to be the heroes while the "replacement" beings lock down the city...but that is all that happens in this book.