It's actually a western. I was trying to make it science fiction or steampunk, but I can't see how that would work since everything I thought about sounded contrived. It may evolve over time, but for now it's just a simple western.
The story starts with two best friends who live and work on a cattle ranch at the end of the 19th century. Haven't figured out where or the exact date yet. The one man is the son of the owner of the ranch, the other is the son of the head cowhand. The cowhand falls for the daughter of the local general store but she doesn't know it. She goes east with the ranch owner's daughter to Philadelphia to go to finishing school. The ranch owner's daughter stays in Philly to get married and the ranch owner's son goes out to Philly for the wedding and to escort the general store's daughter home. On the way back, they fall in love. When they return home they get married and the cowhand admits to his friend that he's in love with her.
Years go by and the couple have two daughters. They do have 2 sons, but both die before their second birthday. They live on the ranch so the cowhand sees her all the time and doesn't have a chance to fall out of love with her.
One fateful day, the ranch owner's son has an accident and is badly wounded. They are able to bring him home but he only lives for about a week before he dies. His wife blames the cowhand even though he tried to save him and brought him back. She comes to hate him and there's a lot of friction between the two.
The ranch owner (who has to take back control of the ranch that he'd given to his only son) is worried about nefarious men who would marry his daughter-in-law to gain control of the ranch so he passes half ownership to the cowhand. This infuriates his DiL and more friction occurs.
Her two daughters are very fond of the cowhand and the eldest who is eight has a crush on him. She tends to show off and will sneak out late to listen to him play his guitar.
That's the basic story, and I have to flesh it out more so I can attempt NaNoWriMo this year.