Before we get started, we'd like to clarify this story's chronological relationship with two others:
In, "Gerfürters! Get Your Hot Gerfürters, Here!", Sashi returns to her home, on Scethos, where she comes across a wild animal, known as a Coxiavor, which is being abused for profit. Being Sashi, she vows to rescue it and return it to its home.
In, "The 'Missii'", Alethea describes the expedition she and Sashi undertook to locate a mysterious race known as the 'Missii'. Their reasons for wishing to meet with them were twofold. First, they wanted to try to establish whether the Missii were, truly, itinerant traders, or something less praiseworthy. Second, Alethea was hoping to obtain an upgrade to the Gas Dynamic Mirror Fusion engine which powers her ship, Leġnis, so she and Sashi could reach the Coxiavor's home planet - Epsilon Tymia III - and return on a single fuel load.
This, the final story in the 'trilogy', contains sufficient background from the previous two to permit the reader comprehend it. If, however, you're a stickler for chronological accuracy, I invite you to read this report after "Gerfürters! Get Your Hot Gerfürters, Here!" - read it, and "The 'Missii'" - read it.