The Alien Intelligence by Jack Williamson

At the coming of day we were walking over a gently rolling scarlet plain, scattered with gigantic solitary boulders, that sloped gradually down to the Silver Lake. The lake lay flat and argent white, clad in all the ominous mystery of that strange world, calling, beckoning us on, challenging us to learn the secret of the fartherest bank of purple fog, with a grim warning of the doom that might await us. The red fern-like sprays waved gently in the breeze, and the vivid, tiny white flowers seemed to sparkle with a million glancing rays, like frost in the sunshine; but the deep intensity of the red color lent a weird and unpleasant suggestion of blood. Beyond the Silver Lake, low hills rose, faint and mysterious in the purple haze.

Melvar walked beside me when the way was smooth enough; she was talking vivaciously. She had a keen sense of humor and a lively wit. She seemed to have an almost childishly perfect faith in my power and that of my guns -- but I was far from feeling confident.