This is actually an alteration on a previous logline I posted. The rough idea is that this society relies on magic and have been taught to fear non magic people and to escape them they shipped off into space. However some people are born without magic and those people are killed. The people turn a blind eye to this out of fear. When his sister disappears he decides to go looking for her and at the midpoint he discovers they’re still on Earth and that the people without magic are being killed. He finds his sister in a civilisation outside the ship and then he decides to head back into the ship to free his people.