Grace Conns has never even been to the Moon before. So when she announces her intentions to search the galaxy for her older brother, Barto Conns, family friend Jyl Hong is more than a little concerned.
Grace isn’t going to let that concern stop her. With her parents dead her brother, sentenced to a prison ship 10 years previously for smuggling, is the only family she has left. She is used to getting what she wants; she wants to find him.
But Grace doesn’t know that others have found her brother first. Ozelle Samoy, a powerful businessman, and Daf Ord, a friend from Barto’s past, have come in contact with the ex-convict. And they have plans for him – plans that will be fatal to Barto and detrimental to Earth.
With the help of a couple of mercs (mercenaries) Grace will set off to find her brother, not realizing the stakes are her home planet. And in the journey she will discover that before she can save her brother or her world, she will have to save herself.
You've got the start of the story but no sense of what the stakes are. "the stakes are her home planet" is meaningless.
And holy moonbeam, "saving herself" is just utter cliche.
Be surgically precise in your description.
Your first sentence is the best.