The second sun was setting in the sky, finally following its sibling beyond the western dunes. The squad had been hiking all day. They'd been out on a scouting mission when their half-track gave up the ghost, leaving them 20ks from HQ. Still, at least they weren't going to get wet walking home; it hadn't rained in the Northern Hemisphere of Kataan IV since the Great Storms, over three decades ago.

As they scrambled up the giant sandbank ahead they knew from the top they should be able to see headquarters now only one or two kilometres away. The Sergeant peaked the crest first, standing tall in the fast dwindling amber light. Sure enough, there was HQ, bright and shining with searchlights scouring the nearby plains.

Directly ahead at the base of the dune was a depression, approximately 500ms square. Entirely in shadow, the western dunes blocking out the feeble glow, this was the perfect place for an ambush. The Sergeant signalled his men to stay alert and slid softly down the sandbank.

The ground as the base of the depression was covered in large mounds. About half a metre tall, almost completely uniform, there must have been a hundred of them within the range of their gun lights. It was eerily quiet. Once the suns set the desert would normally be rife with insects and lizards, searching for food before the temperatures dropped below freezing point, but here there was nothing. The sun finally dropped away and took the orange highlights on the surrounding dunes with it. Now the squad was left with nothing but their small gun lights to see by.

The Sergeant led his squad through the darkness, picking his way through the mounds with careful haste. By his estimate they were halfway across when the first noise rang out. A soggy splintering, like a wet branch snapping, followed by a heavy thud as something hit the sand. The squad whirled, aiming their lights over the ground, trying to locate the source of the noise. But the...