A Nanny is mysteriously directed to the wrong house and is demanded to kill captive children for a soul hungry Entity whose time is running out to earn immortality; she must choose to save the children and escape or be tortured, forever captive with them.

There is no industry wide convention for logline formatting as there is for script formatting for example but loglines are a common tool used in the industry to sum up a story.
Whether you use this tool to structure or pitch the story will determine what type of logline you need.

A pitch logline will likely benefit from less words, 30 and under, and focus on "hooks" this type of logline should be used after a script is finished and ready to be shopped around.

A structuring logline should focus on plot and character as this will road test the concept via the core elements of your story and help you structure the whole plot for the script.

I'm not sure what stage of development this concept is at and unless told otherwise I and most members on this site comment under the assumption it is still in its early structuring stage. If this is the case all previous comments still apply, if not and you are about to pitch the script then perhaps best to re think the logline with a focus on the stakes characters and the inciting incident and less about the genre.

And yes I to find this web site is like a gold mine of feedback...

Great idea recording the logline and playing it back later. That's gold...

There might be a balance to strike here. And possibly a word count limit to test. One way I did my most recent post (face palms because I could have done it sooner) was to read it out loud into my digital recorder and let an hour go by, come back to it and listen to it. If it confused me then it became clear something in that log line came from my imagination (to explain as a log line) versus explaining like a news headline.

Hearing it out loud on a recording exposed the issues. Some were glaring. Other parts of the log line were clear but the sequence of the log line was "off".

So, I had to write it like a before, during, and after news alert.

A news channel is sometimes a great way to learn concise story-telling. And every once in a while, someone captures a story perfectly with just the right amount of description. Plus, it's understandable and it would be possible to say to say what they said as an elevator pitch.

Difficult to so, but so worth it.

*rushes to his library to re-read "Selling Your Story In 60 seconds" again...

I couldn't agree more with. i feel like I'm having the same issues with my log line: too much info, too little info

I recently learned in a highly regarded screenwriting class (which I completed over 10 months) that log lines essentially have to be "hooks" or "highlighted inciting incidents" within the story that could very well grab attention.

And a hook (according to this class prof) won't tell the entire story as you advise (it's great advice, no doubt.)

In here I am testing my hooks and it's not going well because practically every log line i produce here is failing to create an entire story in one line.

And it's a thick story to distill down to three parts (and keep it at 30 words or less).

I may have to feature a log line that simply describes the first act and final act.

Making a psychological horror script visual ( and under 30 words) seems just about impossible (oh I'll nail it at some point I know) unless I cite the gore/violence factor within the story.

And please don't think the frustration is getting to me. Oh no, just the opposite, I love the challenge and at some point the log line will be written clearly enough. It's just a matter of time and effort.

Thank you for taking the time to comment!

Finding this site has been like finding gold!

Bscott.

A logline has a known formula that it needs to follow. I'm not saying that story's have formulas but log lines present specific story elements in a specific way. The comments above are indicative of a fundamental problem in the construct of your logline not necessarily your story. The story may be perfect as is but we are unable to understand it as the logline fails to describe the story using the known story parameters that a logline needs.

This is the logline formula:
After a significant event happens to a main character with this specific flaw he or she must take this compelling action to achieve this clear visual goal.

In your logline:
Significant event - I can't see one in your logline this is the inciting incident that starts your MC off on their journey and needs to be present in the logline.

Main character - is the nanny.

Flaw - Bipolar disorder, however I would argue this is a disease not a character flaw.

Compelling action - "...discover her mental/emotional/spiritual power?" this is not compelling enough and would mostly be an internal process for her not external one for the audience to see.

Goal - destroy the entity this is a good visible goal we can see her killing the entity or sending it back to where it came from.