Corinna Bechko & James S.A. Corey 
Expanse #2 [PDF ebook] 

Avasarala is approached by the cabal behind the black market Martian weapons dealings, who offer to help her reclaim the thing she wants most — her former political power. Trapped between a return to glory and a chance to do the right thing, Avasarala’s ultimate decision will lead to fatal consequences. Meanwhile, Bobbie has made a breakthrough in her investigation — but every victory comes with a price…