The Stalkers by Terry C. Johnston (Plainsmen #3)

Used; Paperback - very good; 1990 1st edition, 1st printing; a small tear in the cover on the spine. Spine a little cocked, some foxing. 

Entrenched on a poorly sheltered island, many of Seamus Donegan's crack squad of Army scouts lie dead--and many more are dying. Led by Colonel George Forsyth, fifty seasoned plainsmen had combed the Colorado Territory in search of Cheyenne. Along a fork of the Republican River, these brave men suddenly found themselves outnumbered twenty to one. Now Donegan, his fellow scouts, and his long-lost uncle are trapped--and under attack. As the battle rages, Donegan is stalked by a traitor who seeks revenge for old wrongs. Together the dwindling band awaits a heroic last-minute rescue from the merciless nine-day seige--known today as the Battle of Beecher Island..