The 20s are roaring. Prohibition makes them roar even louder.

After a month in the wilds enforcing Prohibition, Marshal Merck (Wednesday) McIntyre returns to Winston, Idaho to find a striking woman named Jenny Roades waiting for him. She demands McIntyre put an end to the gang that is forcing her father to surrender the medicinal whiskey in his pharmacy. At the same time, Father Brynn of St. Rafael's has been ordered to deliver up his shipments of sacramental wine to the same gang or see his church put to the torch.

McIntyre knows this gang well. He has tangled with them before. Their calling card is the Jack of Diamonds. But the problem of dealing with the gang becomes far greater when Jenny's father is gunned down and she heads out to seek revenge. McIntyre and his posse can either ride with her or stay behind. But for Jenny Roades, a private detective badge in her pocket and a Colt pistol on her hip, there is no stopping until justice is done.

"I'm not turning back. Everyone else can do as they please. I'm not done till that killer is my prisoner or under the stones."