The title is referencing a ’60s movie, I think. Nothing particular is happening at midnight, as far as I know.
All that happens at midnight is that the clock rings, which is pretty late if you're in the 16th century. The scene is two old men reminiscing about their wild youth:
"We have heard the chimes at midnight"
"That we have, that we have, that we have"
As someone who lives in Lincoln, in the hearing of the bells I quite like it, but I'm not so close that it keeps me awake!