If you are trying to open this file, you will need a utility like 7-Zip or WinZip to extract its contents and see the "story" inside.
A 7-Zip file containing a visual novel, a game's story assets, or a collection of digital stories. MAIS.7z
It is highly probable that this refers to one of the following: If you are trying to open this file,
Can you provide about where you saw this name (e.g., a specific website, Discord server, or game modding forum)? a game's story assets