Is this
Maelstrom the one you are talking about? I have no idea about this Story Engine that you mentioned, but it's the only RPG I know of with that name.
If it is, then yes I have played - and run - it and I love it to pieces. A much more realistic version of WFRG and with magic being very powerful, but also likely to get you killed or make nasty things happen to you. From what I remember it was like a proto form of Paradox from M:tA. The more coincidental the magic the easier to cast and the less likely it was for you to be lynched as a witch.
I also loved the herbs section in it and used to use it for other games until I discovered the herbs section in Rolemaster. Also the adventure in the back of the book was something wonderful and the maps were all those old style road maps where they just trace a line from one town to another and just give distances between things on that line.
There was a problem with character gen and some people ending up vastly more powerful than others, but apart from that... superb.