Either you've already read Illuminae, in which case I don't need to tell you to read this, or you haven't, in which case, you should definitely go read that first!

Anyway, as the Hypatia is bound for the Heimdall station, this is where the story continues, where we discover exactly why the station hasn't responded to their distress calls. I should probably stop here, but imho this book is even better than illuminae... Just read it already!