The Stepping Stone

They try to land a crippled spaceship without notice in a place where people shoot first. The survivors aim for the colony, only to find it gone. Bad news on a planet that digests humans. Worse, part of their cargo escapes, threatening planet wide devastation. Then the Gols drop in, on their way to wipeout humanity. Things happen, and worse.
The sole survivor has to stop the Gols here and now.

Gols and their tech are faster, better, and tougher than humans and human stuff, but they have to land their ships once in awhile for maintenance. Fighting for humanity but following the rules, electronic entities decide that Al is only safe enough to be given an old hunting rifle. He's then told to hunt kilometer tall spaceships full of armed Gols. Thankfully, the escaped cargo demonstrates that it's a hyper-efficient hunter-killer, an old friend well known to the Gols. That reduces the original problem, stopping the Gols at this stepping stone, down to size.