Battlestar Galactica S01 E04 The Lost Warrior

"The Last Battlestar Galactica Leads a Rag Tag Fugitive Fleet on a Lonely Quest for a Shining Planet Known as...Earth."

Apollo is marooned on a Western Frontier-like planet, where he meets a woman and her son ... and a damaged Cylon, known as Red Eye, who has become a notorious gunslinger.