A retired homicide detective must figure out why everybody below the age of 65 have died at their computers, which are all running a pointless game where avatars are stalked and killed by a monster. To make matters worse there’s nobody left to run the nursing home, food is running out, and Mrs Everett needs to go to the bathroom.

No need to get all that into the logline most of what you wrote in your last pot is back story, your logline needs to describe the forward motion of action in pursuit of a goal not the past.

After the sudden death of all people under 65 a retired detective must investigate what happened in order to do what?

This is most of your logline as it describes the plot that will be in your story only thing that is not clear at this point is what is his goal. If all under 65 died and no one over 65 will die so now what? That is a bad thing but what will happen if he fails or succeeds? What is there left for him to do? What are the stakes?

Thanks for your answers. Sorry I haven't answered sooner. I'm gonna try to come up with a new version of the logline soon.

Yes, all people under 65 around the world have suddenly died and that's why the retired detective is the only one who can work the case, at least in whatever city I decide to set this story.

I'm considering making him computer illiterate, or at least uncomfortable with technology so that will be an obstacle to overcome.

The idea is that everybody under the age of 65 uploaded their minds into cyberspace and ended up being trapped there with no way back so their bodies couldn't get water and nourishment and so on, so they all died leaving their minds trapped. And nobody remembered to let those over 65, who were considered incompatible with the uploading technology, know that everybody else uploaded themselves. ... Only I couldn't get all that into the logline, or it would have been even longer.

I'll see what I can do with the next iteration of the logline.

This logline is confusing because it has many elements that are not directly connected through a clear cause and effect relationship and seam incidental to the plot.

Simplify the structure by omitting anything that is not crucial to the story. Main character is the old detective but what is his goal? Is it to stop the death of more people under 65? Is it to catch the killer? Is it to prevent retirees from being killed?

When the logline specifies everybody under 65 is this in his nursing home or in his country or around the world?
Point is the inciting incident needs clarification and needs to be described in less words. For example;
After all people under 65 around the world drop dead a retired detective must?

Hope this helps.

You got a great concept there. I suggest though that you add a hint as to either why he retired too old for this shit or dramatic backstory) or hint at the connection of why the detective himself must be the one as opposed to nonretired detectives.

Sounds like it could be an interesting story, but the log line is too long and confusing.