Another Type-Moon title that has a similar world setting to Fate/Stay Night and Tsukihime Princess.

A series of brutal murders are taking place. Mikiya hears about the murders from his cousin who leads the investigation and Shiki, one of his highschool classmates ends up being one of the suspects. Concerned what might happen to Shiki, he decides to find out the truth. He refused to believe someone like her would commit such murders.

Some years later, both he and Shiki are working for a paranormal investigation agency. The founder of the agency, Touko was a magus who discovered Shiki had the "Mystic Eyes" ability that allows her to put an end to anything. Not only that, she also has the constant urge to kill. As strange, brutal murders take place once again and Shiki missing alibis, her relationship with Mikiya is tested to the limits while he works to get to the bottom of the mysteries.

I'm not a particular fan of Kalafina but their vocals and Yuki Kajiura's compositions create some really great music in this series of short movies. They're mostly dark and gloomy as you'd expect from a show filled with horrific murders but there are some nice serene tracks. Especially as the series wraps up.

There's a total of 7 short movies so it's not your regular OVA or short series. It's a very gorey show with lots of decapitation. Character designs aren't that great to look at, a bit plain looking at times but the direction is quite intense as you feel the trust being tested between Mikiya and Shiki.

An eighth movie "Future Gospel" was released after the original intended 7 which kind of takes place after the 5th and 7th movie (yes, the ordering is horrible in this series!) and is a big contrast compared to the mostly dark and gloomy rest of the short movies. Don't miss it if the 7th movie's ending wasn't enough of a wrap-up for you.

There is also a single movie called "Gate of Seventh Heaven" which summarises the first 6 movies (in chronological order) but you'll be missing out on a lot of the plot. The recap movie is more like a speed run through the ending scenes of each short movie with the theme songs playing; like a very boring music video, missing out the context and build-up so it doesn't have as much impact as watching the individual movies. If you're hoping for some new scenes there are few and not worth seeing really.

Just go for the original short movie series (as confusing as the ordering might be) and the eighth bonus movie if you decide to watch this.