The Enterprise arrives at Gorgeous Springs as the Jennings family arrives in their wagon. The father, Gould, has his younger brother Barry put the wagon team away while the rest of the family goes aboard. Newly married Lovie complains to her husband Rush Jennings that she's never been on a riverboat before and he tells her that she'll be fine. Gould's wife Charity sends Rush to help Lovie, while Carney watches the family come aboard. He notices that Rush is carrying a box labeled "explosives" and runs to the pilothouse to tell Bill.
As Bill goes down to the deck, he finds Grey and tells him about the explosives box. The Jennings family arrives and Gould does the introductions. When he wonders where the rest of the crew is, Grey explains that most of them went into the hills to hunt for fresh meat. He offers to take the box from Gould, but the man says that he'll hold onto it and that they're taking it to the Fletcherville Fair. Gould takes the box to the grand salon to show Grey and Bill what it is. When he opens it, Bill and Grey are surprised to discover that it's a watermelon. Gould tells them that it's the most perfect watermelon in the country. Bill puts it on the shelf behind the bar on display and Grey pours drinks so they can toast the watermelon.
Bill tells the Jennings family about their cabin assignments, including the fact that Lovie and Rush will be staying in the deluxe cabin. Upon hearing that, Grey takes Bill outside and warns him that he already booked the cabin to the Cox family two weeks ago. Bill didn't check with him because they were running close to empty, and refuses to move them. He points out that Gould was determined to get the deluxe cabin and he has a big gun.
The Cox family arrives and Grey points out to Bill that they also have big guns. Grey goes to greet Niles Cox and his family while Bill tries to talk Gould out of taking the deluxe cabin. Niles introduces his attractive daughter Inez and orders Grey to give her a small private cabin while he and his son Salem take the deluxe cabin they paid for. Grey tries to fend him off but Niles insists, pointing out that he paid half up front. The captain reluctantly takes them to the cabin.
Grey keeps trying to convince Niles to take another cabin but he says that when they travel they always go first-class. Grey offers him a refund, saying that there's been a mix-up, but Niles refuses to take anything else. Inez sees Barry approaching the dock after putting the team away and tells Niles, and he opens fire on the man. Grey shoves the rifle barrel up and stops Salem from opening fire, and Bill and the Jennings family runs out. When they see the Coxes, Gould opens fire and Bill ruins his aim, and both sides duck for cover.
As the two sides shoot at each other, Grey calls Carney and tells him to heat up the boilers. Bill gets Lovie and Charity into the deluxe cabin while Niles explains to Grey that the two families are blood enemies. Gould tells Bill the same thing and admits that they've been fighting for 50 years. Meanwhile, Barry dives into the water to get ashore and go for reinforcements, while Gould wounds one of Niles' sons at the dock. Niles yells to his sons to get reinforcements and tells Grey that the feud is on.
Grey goes to the boiler room and confirms that Carney has the boilers ready. Meanwhile, Bill makes his way to the pilothouse and calls Grey. Grey tells him to be ready to leave, tells Joshua to guard the door and let no one in without his giving the signal, and then goes back up on deck.
Salem and Inez go looking for the Jennings, and Lovie and Charity leave the cabin and spot them. They warn Rush and the two sides starting shooting again. The Coxes run back to cover and when Rush tries to shoot them, Charity stops him because Grey is in the way. Meanwhile, Grey spots Barry in the water and throws him a line.
Bill tells Gould to protect the pilothouse in case the Coxes rush it, while he takes the Enterprise out. Meanwhile, Grey puts Barry in a storage closet and locks the door, and then grabs an axe to cut the mooring lines. Inez notices him coming out of the storage closet, and Grey says that he went there to put the axe away but realized that the door was locked. When Inez prepares to shoot the lock off, Grey distracts her by flirting with her. She says that she's not engaged and starts flirting back, but they're interrupted when the families start shooting again. Inez goes to check on her family and Grey cuts one mooring line. Once he's severed it, Grey gets into the water and swims around to the other side to cut the last line, and then signals to Bill to pull out.
The Enterprise leaves the dock and Niles and Salem realize that they're trapped. Grey runs into Inez again and she notices that he's wet. She goes over to the storage closet again and Grey distracts her by asking if she's engaged. Inez wonders if he's flirting with her and Grey admits that he is. She eyes him appreciatively and says that she'd be glad to have a riverboat captain. Speaking bluntly, Inez tells Grey that she likes him but insists that she's going to kill a Jennings before she dies.
Niles goes looking for Inez and finds her with Grey. Grey avoids telling him that he cut the mooring lines and Inez, realizing what Grey did, covers for him. Niles draws his gun and orders Grey to take him to the boiler room so that he can stop the riverboat. Grey does so but gives the wrong signal to Joshua. The first mate refuses to open the door and when Salem tries to break it down, Joshua fires over his head, scaring him off.
Niles tells Grey to open the door or he'll kill him. However, Grey takes the approach that Niles is a civilized man and would rather talk than fight. The captain warns Niles that they have enough wood for the Enterprise to reach Fletcherville, and asks how the fighting started. Niles doesn't remember and explains that the only church in Gorgeous Springs is neutral ground for the two families. Grey points out that he's married people on the ship, making it holy ground, and tells Niles to pretend that it's Sunday for the next two days until they reach Fletcherville. Niles reluctantly agrees to let Grey negotiate a parley between the two sides, and Grey says that he'll have to talk to Bill via the pipe in the boiler room and confirm that he's okay.
Once Grey gives the proper signal, Joshua comes out and accompanies Grey to the pilothouse. Grey tells Gould that he's bringing Niles to the grand salon without his guns and tells Gould to do the same thing. When Gould realizes that they're trapped, he agrees to parley and Grey tells Niles that the war is about over. However, the elder Cox isn't so sure.
The Coxes get to the grand salon first and leave their weapons at the door. Grey notices that Inez hasn't handed over her revolver and insists, but she refuses until Niles orders her to obey. Bill brings in the Jennings family and Gould holds up his gun... and hands it over. Grey begins by taking out some history books about war and explaining that even the longest wars haven't last more than ten years. He wonders why their war has been going on five times as long and neither man speaks. Charity finally speaks up against Niles' wishes and tells Grey that they have been feuding about land. Fifty years ago there was a drought in Gorgeous Springs and the Jennings found a spring on their lands. The Coxes tried to fence it off, killing seven Jennings men, and the fighting began. Since then, no one has used the spring. They don't need it anymore because they have found other springs and there haven't been any more droughts.
Grey figures that the spring has nothing to do with the feud anymore and says that the only way to end a war is for someone to win. He says that either they can wipe each other out or end it without bloodshed. Charity is in favor of anything that saves lives and Grey suggests that each family pick a champion and then the two men will fight without weapons. Lovie speaks up, saying that she doesn't want to see her new husband dead, and Charity encourages Grey's plan. Niles admits that it's tempting but dismisses it as nothing but a dream. Gould seizes on the opportunity to say that Niles is afraid that his family would lose, and Niles says that his son Salem can whip any man. The elder Jennings boasts that Rush has never lost a fight and Rush agrees to fight. The two families agree that whoever loses will give up the spring to the winner.
That night, Rush and Salem prepare to fight while Charity approaches Grey and thanks him for stopping the feud. Meanwhile, Inez takes out a hidden revolver from her purse and goes back to the storage closet. Barry has finally decided to unlock the door and come out, and finds Inez waiting for him. She's eager to kill a Jennings but Barry doesn't believe that she can do it. Inez tells him to stay put while she considers.
The families gather on the deck to fight and the two men start... just as a gunshot rings out. Barry runs up the ladder and Inez shoots him in the back. Grey runs over and confirms that Barry is still alive, and refuses to give the guns back when Gould demands them. Niles slaps Inez, furious that she's broken his word and shamed him. Upset, Inez bursts into tears at the thought of having killed a man. She admits that she didn't know what she was doing and Grey shoves Niles back, saying that both sides passed their hate onto her.
Grey tells Inez to go to her cabin but she dives over the side instead. Grey dives in after her while Niles, Gould, Rush, and Salem take a lifeboat to shore. Meanwhile, Inez makes it to shore and runs off into the nearby swamp. Grey goes after her but is unable to find her in the darkness. He goes back to shore and gets the four men. As they prepare to search for Inez, Gould offers to help, much to Niles' surprise. However, he gratefully accepts his enemy's help.
The men split up into three parties to search the swamp. As she runs through the swamp, Inez twists her ankle but limps along. She finally falls into quicksand and Grey follows her screams. He calls to the others, tells Inez to keep still, and tries to reach her with a branch. It isn't long enough and Grey has the men form a human chain so that he can pull Inez out. Niles goes to his sobbing daughter and hugs her tight.
Later, the Enterprise continues to Fletcherville and everyone gathers in the grand salon for a drink. Grey proposes a toast to fifty years of friendship after fifty years of warfare and both families join in. Niles notices the watermelon and admires it, and he offers to cut it and celebrate. Grey looks at Gould, who draws his knife and looks at Niles for a moment... and then gives it to Grey and tells him to cut it so they can share it with their good neighbors.