The date is 1881; the scene, the western frontier—Texarkana, Arkansas. Reports of a monster living near and around the swampy lowlands, not a day's ride from the town, have sparked the interest of a well-respected, medical doctor in Boston. Only in his thirties, Dr. Reginald Cook (nicknamed, "Bones") is approached by government officials to investigate the massacre of army corpsmen that took place near Boggy Creek—the swamp area near Texarkana.
Dr. Bones takes up the challenge and is joined by a woman whose wealthy family decides to help the doctor with his travel expenses but on the condition that her daughter and nephew go along. The doctor arrives in Texarkana only to discover more than just an alleged attack by a monster. Quickly, he becomes embroiled in something far bigger, that could end disastrously—both for the town and for the three monster hunters.