Whose Party is It Anyway?

Houston goes to the office to meet some people who asked to see him. But when he gets there, he learns that they think he asked them to come. But Houston doesn't know all of them. But then one of the guests says that they do have something in common but that's when he's killed. And they find themselves locked in. And that's when someone is sending them messages which are suppose to be hints of why he is targeting them. And more people are getting killed. And more messages are being sent.