"Chandra's Pup" by Bud Sparhawk

A story set in interstellar space in a time where humanity has spread to the stars. Near one colony world, a military ship encouters what appears to be an alien ship, igniting what may well be man's first war with an alien species. In an attempt to understand the alien, the military enlists the help of a scientist who is adamant the alien must be peaceful and that the military has spoiled a chance to meet an alien species in peace. But as the stories continue, it becomes increasingly difficult to know whether the alien ships are peace or not, or even if they are alien ships.

• Read from Analog SF, July-August 2005 issue