I posted about how to read LIB.CLU here:
https://moddingwiki.shikadi.net/wiki...Cluster_Format
I know that the description there might be a bit "dense", it takes a bit of playing around with it to see what I meant. To help, you can search LIB.CLU for "Annonay", where the text just happens to be unencrypted (because the cluster ID value just happens to line up to where no text changes), to get an idea of how the file is saved. From there you can try decoding the actual plot instructions if you want; I had gotten through quite a bit of it, but never posted about it because I never finished it. Let me know if you want help with that.
Note that on the same website, I also posted about how the save game file is stored, in case you want to edit the save game files.