Paradise: Expeditionary Force, Book 3 / Craig Alanson

While the crew of the starship Flying Dutchman have been trying to assure people that hostile aliens do not have access to Earth, the UN Expeditionary Force has been stranded on the planet they nicknamed "Paradise". The Flying Dutchman is headed back out on another mission, and the UN wants the ship to find out the status of the humans on Paradise. But Colonel Joe Bishop warns that they might not like what they find, and they can't do anything about it without endangering Earth.