When in a village destroyed by war something in the shadows begins to haunt and torment him, a dreamy child must fight to survive and find some happiness along the way.
For coherence, I would rephrase to “In a village destroyed by war, when something….”
A logline doesn’t bother itself with the internal arc. The search for happiness doesn’t need to be stated. However, if you changed “dreamy” to “sad” or “depressed” this hints at the internal arc.
“Something in the shadows” – I know this is only a short but it might be worth being a little more specific. You’ve only said this “something” haunts and torments him… not that it’s actually trying to end his life. I think this is quite important. Can I ask what it actually is that is haunting him?
You don’t have to take this suggestion but the lead character should have a tangible goal.
Perhaps he is searching through his destroyed village to discover whether his mother survived.
As he searches, he is tormented by ghosts but he refuses to give up because he must know if his mother is alive.
Anyway just a thought, take it with a grain of salt.
For me, I would swap the clauses so that the child appears first and then the village:
A dreamy child must fight to survive when her village is destroyed by war.
Then I’d try to hint at a specific goal and specific antagonist.
A frightened child must escape the clutches of human traffickers when they destroy her village and murder her parents.
An imaginative four-year-old makes a harrowing journey to a neighbouring tribe when her village is destroyed by militants.
An isolated child must use all her smarts to survive in the wild when her village is ransacked by imperialists.
Or whatever suits!
If it’s for an animated short I can see where you are going. What is the child doing to find happiness? Is he looking for a place without war? Maybe something like this…
A dreamy child seeks refuge after his village is destroyed and manages a positive attitude even though the entire countryside is a violent battlefield.