Andromeda by Claymore, Andrew G.

What would you do if you discovered a gateway to another galaxy? Gabriella may be an unlikely planetary governor but her people know she’s earned the role. Now she’s leaving her colony to lead an expedition through the gate. She’s looking for Humanity’s lost ancestors, a race of giants with the technology to reach out to other galaxies though it ultimately led to their doom. That kind of power breeds enemies… Their trail went cold eons ago and leads through hostile territory. As casualties mount, Gabriella must decide if the cost is worth it. For someone who watched her own mother die – twice – the cold math of leadership is tearing open old wounds. Back home, our forces are embroiled in an alien civil war. New enemies are the last thing we need. We are surrounded. We are alone…