When a nice holiday cruise turns bloody, a detective is able to eliminate the murderer after his son surrenders himself to lead the detective straight to her.

As Nir Shelter said, ?it's confusing.

And it seems to give away the ending, the solution to murder, something a logline should not do. ?A logline implicitly raises a dramatic question, but it never answers it.

This sentence is confusing, I'm not sure who does what and why.

Who is the main character?
What is their inciting incident?
What is their goal?