Ah, missing cat stories. Mine fell into the neighbor's cellar once through one of those ground openings. Missing for a day, I was worried, but on the second day, well, his tendency to respond to my voice finally got through again (must have been too scared to do anything the first day), so when I heard those crying meows from down below, all I could do was knock on the ground floor window and ask if they could let me in to pick him up.
A nice old lady opened up for me and when she opened the cellar door the poor rascal just darted for me and gave me a kitty cuddle of his life. I bought the nice lady a box of coffee for being kind enough to let me get him instead of telling me to get lost as some people would undoubtedly have done.