When a young man washes-up dead in a desolate coastal town, his self-centred estranged mother must fight against apathy and hostility to uncover the truth, at the risk of exposing her own culpability.

>>>the reveal that the drowned man is the protagonist's son comes at the inciting incident ? there's mystery up until that point as to what relationship,

In the script , you can certainly open with nobody knowing the ID of the washed-up body.? For the purpose of a logline,? where economy of words is paramount (less is more, fewer is better),? it isn't necessary.? Rather, it's superfluous.?A logline begins with the inciting incident. -- not with with happens before that plot beat.

So CraigDGriffiths lead off --" When her estranged son is found dead" -- does the job.

>>>the reveal that the drowned man is the protagonist's son comes at the inciting incident ? there's mystery up until that point as to what relationship,

In the script , you can certainly open with nobody knowing the ID of the washed-up body.? For the purpose of a logline,? where economy of words is paramount (less is more, fewer is better),? it isn't necessary.? Rather, it's superfluous.?A logline begins with the inciting incident. -- not with with happens before that plot beat.

So CraigDGriffiths lead off --" When her estranged son is found dead" -- does the job.

If the mother is the MC best to re write the logline from her point of view.

After her son is killed, a self-centered woman must fight to...

What do you mean by her own culpability? Did she kill him? Did the son kill himself as a result of something she did?

Lastly, what apathy and hostility is she fighting?