After finding herself trapped in the afterlife whilst attempting to contact her deceased mother, a neglected young girl must battle through the land of the dead to find a way back to the living or risk being trapped forever.

As variable recommended, check out the rules and try and start with the inciting incident, then the goal, then the stakes. My example is a bit wordy and is probably not the story you have in mind but you get the idea.

I think MarinaM might be asking if her age and whether her mother being recently deceased is significant enough to include in the logline. In my mind, they are only significant if something else in the logline makes them so. If the mother being recently deceased is critical to the girl being able to contact her then include the reason as the ticking clock aspect of the logline e.g. before her mother is lost in the afterlife. With the information above, I think just calling her young could save you a couple of words without losing anything.

Hope this helps.