Nancy just finished up a case and spent the last 30 hours on her feet, but she promised Ned that she'd go to a lecture with him at his college. Bess and George meet them there. Tracey Gaines, the granddaughter of two famous gangsters, just finished up a big project and wants to share what she learned. Nancy keeps falling asleep, and at one point, Ned wakes her up. She notices him wearing a suit exactly like every other man in the crowd, and all the women are in dresses. A newspaper she finds lists the date as 1930, the same year the woman researched.
Bess and George find a very confused Nancy outside and start talking about taking bread to Hooverville. It seems as though Nancy really did go back in time and landed smack dab in the middle of the Great Depression. After seeing Hooverville, they stumble across the Smith family. Clay Gaines and his partner, Edward Parker, are in the midst of evicting the family from their home. Bob lost the house while gambling. Nancy offers to let them stay with her.
After dropping Bess and George off at home, she gets lost because nothing looks familiar. Charlie, the same guy who saves her all the time in the modern era, finds her and helps her get home before telling her that his family is moving on to greener pastures. She gets home in time to see the chief with her dad. The chief tells her to leave them alone, but she does overhear them talking about some big bank robberies. That's when the Smith family shows up.
Carson is nice enough to let them stay for awhile, and Hannah makes a big dinner for the whole group. It's the parents, Bob and Sylvia, their four kids, a pet mouse, cat, rat, and two dogs. Nancy keeps pumping Bob for information on the casino where he lost his house. He keeps pointing out that she's a girl and can't do all the things she wants to do. She just knows that she can figure out what happened and get them their house back.
When Nancy learns that the only school in town shut down because the town couldn't afford to may the teacher anymore, she heads to Hooverville to speak to the teacher. The woman refuses to be a charity case, but Nancy comes up with a barter idea. All the parents will trade different things to get the teacher back. The idea comes to her after running into Ned. He works for the grocer in exchange for food for his family and didn't tell her because he didn't want her to look down at him. Nancy assures him that he's still her guy and gives him a kiss on the cheek.
She goes back to Hooverville the next morning though and finds the police tearing through. Deirdre shows up in a fancy party dress to help the cops find the person who stole an apple pie she made. They arrest a 10 year old boy and take in his whole family on suspicion of being bank robbers. Apparently stealing a pie because you're hungry is the same as robbing a bank.
Carson agrees to go over to the jail and see what he can do, but Nancy gets there first. Chief McGinnis already let the kid and his family go but warned them about stealing. Since Nancy knows Clay Gaines is a bad guy from the future, she brings him up to the chief. The chief thinks Clay is a good guy and actually has plans to meet him later. She drops a bunch of hints about setting up a roadblock to stop the real thief from leaving town. When he finally picks up on her hints, she gushes about how he's so smart and handsome before leaving as she rolls her eyes.
With some help from Ned in the form of suits that belong to him and his dad, Nancy and the gals dress up like gangsters. Since Bess still looks way too feminine, she literally takes them to a farm down the street, cuts some hair off a horse, and makes a fake mustache that she glues on Bess. Edward lets them into the casino after she claims that they know Clay but then slams the door on the them and locks it. He comes back with two other guys and sits everyone down to play some poker. George keeps winning, and Nancy makes an excuse to use the bathroom and take a look around. She finds Clay's ledger with all the proof that he's a thief.
Though the girls want to leave and stop playing, Clay won't let them leave because George is up by so much. Bess sneezes, which causes her fake mustache to fly across the table, and the guys realize all three are gals. After a short fight, they manage to get away. Nancy sends the other two to the police and leads the guys away from them. Chief McGinnis then shows up and stops Clay and his wife. Nancy shows him the ledger, but before he can do anything, they take off.
They don't even get a mile up the road before they run into a slew of cops. It turns out that George called the police departments in every nearby city for help. Chief McGinnis then takes all the credit, but Nancy gets the Smith's house deed from the ledger and takes it to them. Bob is so grateful that he gives Nancy a brand new dress he just made. She then heads to town hall for a special speech, feels tired, rubs her eyes, and wakes to find herself back in the present.
Tracey Gaines finishes up the speech with information on how the official word said that cops from other towns came in to help. Word on the street was that a female dogooder that no one ever named came forward and actually brought them down. Ned thinks that's funny and points out that it sounds like someone he knows. Nancy just smiles.
At the very end, Bess and George take Nancy to meet their Aunt Eliza who lived through the Great Depression. She has a frog that Nancy correctly guesses the name of based on the frog Eliza Smith had in the past but says it was just a guess. Eliza then gives her that look and tells her to stick to that story and that she'll never say a word.
*This book literally takes place less than a week after the last one, which I only know because Ned and Nancy talk about it at the beginning.
*My favorite part of this book is that Nancy has a blue convertible coupe just like she had in the original books when she went back in time.
*Deirdre's family is somehow still super wealthy and has no problems. She even says that anyone who wants to work can find a job, which made me roll my eyes.
*Carson worries about Nancy going out in the middle of the night when it's actually 8:30, but that's still way too late for a girl to be out alone.
*George has two hours to teach Bess and Nancy how to play poker and everything they know to beat the bad guys. That sounds a little impossible to me.