Carson has a big and important job for Nancy. Millionaire Arlo Winthrop desperately wants to track down his daughter Clarinda before he dies. The only problem is that she went missing 40 years ago. After she fell in love with a solider, her father forbid her from seeing him, so she ran away to be with him. Winthrop tracked her to Wyoming, but no one has seen her in at least 30 years. When Carson gets a call that Clarinda is actually in Canada, he decides to try and find her and send Nancy and Ned to Wyoming. They can stay with Grace, the best friend of Nancy's mother.
At the airport, they randomly stumble upon this little girl Jennifer. She's been attending boarding school in River Heights while her mother recovers from a car accident, but her mom called and asked that she come home. The head of the school recognizes Nancy and asks her to keep a watch on her during the flight. Ned winds up really bonding with her.
Once they get to the airport though, her mother isn't there. They look up and call her phone number to find it disconnected. Grace, being a super nice woman, invites Jennifer to stay at her house. Nancy then notices two men staring at them and especially keeping a close eye on Jennifer.
Instead of focusing on the missing heiress, Nancy focuses on finding Jennifer's mom. She and Ned check out the house and find a car in the garage, a newspaper dated a few days earlier, and no sign of the woman anywhere. Two men in a blue car, who look suspiciously like the men from the airport, drive by the house and stare at them before speeding off. None of the neighbors have seen her either.
Also strange is that Carson never calls Nancy to update her on his own situation. She calls Hannah to see if maybe he checked in with her and learns that he hasn't called anyone. Nancy finally calls the lodge where he's staying, but the man who answers is really gruff and says Carson is too busy to talk. When Carson finally calls her back, he doesn't ask any questions or even check on Grace and just says that he's found a lead and is super busy.
Cheyenne, where they're staying, is in the middle of a big rodeo days celebration that lasts all week. This gives Nancy and her group the chance to go to a bunch of parades, square dancing, and rodeo events. At one, someone shoves Nancy in the street and she comes close to getting trampled by a horse before Ned saves her. At another, someone grabs Jennifer and runs off, but she kicks him in the shin. He drops her before hopping in a blue car.
Next, someone hits Grace from behind and steals Jennifer again, only this time, they actually get away. Nancy begins meeting with people to talk about the missing heiress and finds out that the woman actually did come to Cheyenne but that she changed her name before marrying her soldier. They lived on a big ranch until someone robbed the local bank. Police found some of the missing money on their property and blamed them, which led to them leaving the town in disgrace. The real robbers were later caught and admitted to hiding the money there.
Friends of the couple stepped up and took care of their ranch in the hopes that they might one day come back. They leased the land to other farmers and ranchers for their animals. One friend lets them check out the ranch. Nancy finds a diary kept by the woman that mentions people by their initials and learns that two of those initials match the names of friends who later moved to California. Oddly enough, Jennifer has an “aunt and uncle” in California by those same names. See where this is going?
To make a long story shorter, Nancy finds out that the two lived in a small cabin set back from the main ranch. She and Ned then see the same blue car in town and follow it to the ranch. They wait until the car leaves again, track down the cabin, and find both Jennifer and her mother. After breaking the window, they get them out and take them back to Grace's house.
It doesn't take long for the full story to emerge. Jennifer's grandmother is the missing heiress, who now lives in California. They call her on the phone, and she tells Nancy that she actually wrote to her father to make amends and got back a letter from him that basically told her to go to hell. Nancy realizes that the woman's cousin, a man literally mentioned one time on page two, is behind everything. He took care of his uncle and assumed that he would inherit everything. Nancy comes up with a plan to get Jennifer, her mom, and Ned out of town and back to River Heights while she flies to Canada.
After learning the lodge her dad stayed at actually went out of business, she sneaks over and finds that someone is keeping him drugged. She sets fire to a shed nearby to distract the guard and then helps her dad escape. They fly back to River Heights and meet the former Clarinda as she flies into town. Clarinda and her dad make up, and I assume everyone lives happily every after while her cousin and all his helpers do serious jail time.
*Ned says that there being a car at Jennifer's house isn't proof her mom was there because a lot of people rent out their garages to people who have cars when they don't own their own cars. Is that actually common or just something from the west in the early 80s?
*So, Grace is roughly the same age or slightly younger than Carson, yet Nancy always describes Carson as kind of a catch and makes Grace out to be some dowdy middle aged woman.
*Someone sends Nancy a note to meet them at the rodeo's animal corral and then locks her in the paddock with a charging bull. Remembering something she saw in the show, Nancy does some crazy and evasive maneuver to roll under the bull and through the fence. Surprisingly, no one really seems worried that a tourist was almost killed...
*Clarinda changed her name to Lindy, which is the name of the woman who lived in Cheyenne and then moved to California, but it somehow takes Nancy way too long to put the pieces together.
*I pretty much figured out Jennifer was the granddaughter of the missing heiress as soon as she showed up.
*There really is no explanation for why they kidnapped Jennifer and her mom. Clarinda already thought her dad didn't care about her anymore, so it's not like she was coming back to town.