That old mainframe is still chugging along over near the halon bomb.
No one understands its function completely as the people who once operated it have all gone away.
It runs a vintage operating system and software written in a programming language which few people still use.
Perhaps it is not not even well documented.
You need to maintain it or replace it with a modern system, but as it still plays a role in the business process you are not certain how best to do this. A dirty job which nobody wants.
You have come to the right place.