This is another short story, the first of thirteen connected shorts set in Scalzi's Old Man's War universe.
The Colonial Union has a major problem. They're no longer on speaking terms with Earth, so they no longer have Earth as a source of new recruits for the Colonial Defense Force, and they're a couple of generations away from being able to recruit sufficient numbers from their own colony worlds to meet their needs. And meanwhile, about two thirds of their previously divided and chaotically at odds rivals have joined together into the Conclave. The CU needs all the allies it can get, and a race that hasn't been interested in negotiating a deal before now is. They send off the very best diplomatic talent they have--and that team vanishes, their ship apparently destroyed, before the alien diplomatic team could even arrive.
Suddenly the CU is scrambling to save the situation and the negotiations, not to mention find out what happened to their ship. They have to work with what they have in range, though, and they don't have another "A Team" diplomatic team available. What they have available is Ambassador Ode Abumwe and her workaday "B Team" who normally handle much lower-level, routine diplomatic chores.
This time they're being tossed in at the deep end, on no notice, and need to resolve a major crisis, as well as figure out what caused it and who's behind it.
Classic Scalzi. Recommended.