I had high hopes for this, since I enjoyed both the book and the board game from which it takes its inspiration. In practice, though, I find it completely bewildering. During the first part of the game, there's not much to do other than sleep and attend holy services; there's some interesting coding at work here so that whenever bells ring for Matins, Lauds, etc., the player will automatically zombie-walk to the church to attend, but that makes the game somewhat uninteractive at the beginning.
After a couple of services, one of the monks turns out to be missing, and I'm directed to look for him. I assume (given the premise) that he's supposed to turn out to be dead -- but I can't seem to find a corpse, nor do any of the other monks seem especially concerned about looking. So the game continues for quite some time with my aimless exploration of the abbey, interrupted by service after service. (Time passes quickly here, with the result that one is called back to the church extremely frequently. While this mechanic makes some sense in the original board game, it's frustrating in IF form.) At this point I've used up nearly a whole day without having found any clues or having any better idea what I'm supposed to be doing than I had at the outset.
On the one hand: a reasonable amount of work seems to have gone into animating the characters and programming the player to return to the church on schedule, and there are a number of touches where the author seems to have done period research in order to flesh out the settings with appropriate furniture and room descriptions. I'm all in favor of historical IF, so this is nice to see. And from the evidence of the other review, there is obviously *sometimes* more to see than I got a chance to experience.
On the other hand, the gameplay is either buggy or very badly-directed. The story side doesn't do much better, either. The game encourages the player to go around asking the characters about one another, but quite often they have almost nothing to say; responses such as "I don't know him well" are common, which is strange given that this is a very small community of monks who live and work together, and who would be likely at this point to be all too intimately aware of each other's personality quirks. Furthermore, characters show no discomfort discussing third parties who happen to be in the room.
In short: this is an interesting concept that deserves a better execution. "An Act of Murder" shows that the randomly-selected-murderer scenario can work in IF; "The Abbey" doesn't appear to have pulled it off, though.