The Domino Pattern by Timothy Zahn

toward the empty seat between him and Tririn. I actually didn’t need him to move—even third-class Quadrail seats allowed the average passenger plenty of legroom—but it was always polite to ask.
    “Certainly,” the Nemut said. Getting a grip on his goodie bag, he drew in his knees.
    “Thank you.” I sidled past him and sat down beside Tririn. “Good day, Master Tririn,” I said. “Frank Compton. You may remember me from last night.”
    [I remember you, Mr. Compton,] Tririn said, the normal harshness of the Shishish tempered by the listlessness in his voice. [And the day is not good. No days from now on will be good.]
    “I understand.” I said, glancing back at Kennrick. He was still standing in the aisle, glowering at my brazenness at barging in on Tririn’s solitude this way. Bayta, for her part, was standing a little apart from him. up near Terese’s row, where she wouldn’t crowd us but would still be close enough to listen in on the conversation. “Were Master Colix and Master Bofiv close friends of yours?” I asked, turning back to Tririn.
    [They were business associates.] he said.
    “I understand.” I said again, wondering briefly if he was correcting me or agreeing with me. “Tell me, did all three of you eat together yesterday?”
    [We ate sundown together,] he said. [Sunrise and midday were eaten individually.]
    According to my encyclopedia, that was indeed the standard practice for non-family Shorshians traveling together. Unfortunately, it didn’t tell me whether or not the three had been friends or something more distant. “Do you remember what you all ate at sundown?” I asked.
    [The common dish was po krem ,] he said. [It’s a shred, a mixture of meat and fruits.]
    “Yes, I’ve heard of it,” I said. “What reaches did all of you use?”
    For the first time since I’d sat down he turned his face toward me. [My apologies, Mr. Compton.] he said, eyeing me curiously. [I took you to be as other Humans, ignorant of Shorshic custom and honor nodes. For that unspoken slight, I ask your forgiveness.]
    “Freely and openly granted,” I assured him, giving silent thanks that I’d had the sense to sacrifice an hour of sleep last night in favor of a crash course in Shorshic social customs and terminology.
    [Thank you,] he said. [My reach was galla bread. Master Colix and Master Bofiv used baked prinn scoops.]
    So the two dead Shorshians had eaten from the common bowl with the same type of edible scoops, while the Shorshian alive and breathing had used something else. I made a mental note to check with the server Spiders to see if those choices were standard for the three of them, or whether they’d been unique to the fatal evening. “And your individuals?”
    [All different,] he said. [ Birrsh for Master Colix, valarrki for Master Bofiv. sorvidae for me.] His eyes flicked briefly past my shoulder. [Yet the Spiders said the death was not in the food. Do you believe otherwise?]
    “I don’t believe there was any death in the food when it was served to you,” I told him. “But possibly something happened after that. Do you remember anyone approaching your table while you ate? Perhaps to ask a question, or to engage one of you in conversation?”
    Tririn cocked his head in thought. I watched him closely, wondering if he was searching his memory or just trying to think up a good lie. [I don’t believe so,] he said at last. [There were servers, of course, but no one else approached.]
    “Did you happen to notice who was sitting at the nearby tables?” I asked.
    Tririn’s brow wrinkled. [We sat at a corner table,] he said. [There was only one table near us. Unfortunately, my back was to the occupants.]
    I grimaced. “I see,” I said. “Well, then—”
    “I saw them.” the Nemut on my other side volunteered.
    I turned to him in surprise. “ You saw them?”
    “They were Humans,” he told me. “One female, one male.”
    One female … “Was it by any chance that female up there?”