This is quite a tidy one-shot adventure, ideal for new players as it has investigation that isn't overly complicated, combat that can be challenging but isn't necessarily deadly, a mystery to solve and !!SPOILERS!! an unexpected betrayal by a key NPC.
It's set in the usual CoC 1920's New England, I transplanted it to London without any trouble. The only caveat I have is that it needs an edit as some of the dated events which the mystery is based on don't quite marry up and there's occasional text that needs parsing with common sense, any decent GM can deal with it easily but even so, it's not a free product so it shouldn't have that issue.
[4 of 5 Stars!]