The keeper of the Isis light

Olwen Pendennis is the Keeper of the Isis Light. She and her companion, Guardian, have lived alone on the planet Isis since the death of her parents. But then a group of colonists arrives on Isis from Earth, settling in the valleys – the only places where they can breathe and not be harmed by the planet’s harsh sun. Olwen fears these new inhabitants may ruin her world forever, and at first, it appears she is right.