Axl returns home from his summer trip to Europe, sporting a man-bun and embracing a new, chill European outlook on life. Mike just wants him to clean up and look for a job, but Frankie thinks Axl will do this on his own and asks Mike to give him a little breathing room. Meanwhile, because Sue worked the entire summer at Spudsy’s and missed out on having any fun, she decides to cram in a whole summer of fun in two days before going back to college; Brick makes the decision to break up with Cindy because he doesn’t want to be tied down in a relationship when he’s about to embark on the revelry of his “big sophomore year”; and Frankie desperately tries to come up with an item for a time capsule that’s being buried under the Orson cow that will make the town remember the Hecks when it’s opened in 100 years.

After Frankie gives neighbor Nancy Donahue an old scarf that is just sitting around gathering dust, Nancy returns the favor by baking her a delicious apple pie. Believing she’s stumbled upon a way to get free and tasty meals, Frankie makes it her mission to find miscellaneous items around the house to give to her in exchange for some culinary delights. Meanwhile, Sue and Lexie prepare to move back into their college apartment but find that it’s been sublet to a man who refuses to leave; and Axl’s new job as the school bus driver gives him a chance to see how Brick’s high school sophomore year is treating him, and he discovers that Mike has refused to speak to Brick’s class on Career Exploration Day.

Frankie's mom stays with her after becoming ill; Sue suggests to Sean that they should set each other up on dates; Axl and Brick ponder what Mike actually does at the quarry.

The Hecks take a hectic road trip to Frankie's sister's house for Thanksgiving; the kids must decide which one of them will lose their job at Spudsy's.

When Axl visits Hutch, he discovers his friend has turned into a responsible adult; Sue is unable to sleep after watching a horror movie by herself; Brick enlists Frankie and Mike's help to help convince a girl to give him a chance.

Frankie remembers she has to come up with something to place in the time capsule; Bill Norwood informs Mike that he and Paula are separating; Brick tries to win Cindy back; Axl volunteers Sue to be his personal assistant.

Things don't go as smoothly as planned for the Hecks when Frankie helps Sue celebrate her 21st birthday by taking her to a bar close to the college, Mike begrudgingly accompanies Brick to a "Planet Nowhere" convention, and Axl and Hutch head to Ohio in the Winnebago to attend and make a toast at ex-college roomie Kenny's wedding.

While Frankie feels the need to have a good cry after having a bad week, Mike shares the good news that, after 25 years as manager at the local quarry, he is being offered the job of regional manager but feels uncomfortable saying goodbye to his co-workers. Meanwhile, Brick suspects that he's being treated unfairly by his health teacher because of how horribly Axl treated her back when he was a student.

It's the Orson showdown of the century when the Hecks - along with the Donahues and Bill Norwood - wage a war against the Glossners after they steal Sue's car.

Dr. Fulton tells Frankie and Mike that Brick and Cindy have been making out all over the school. Mike tries to teach Brick proper dating etiquette; Sue attempts to give Sean the snow globe, and tell him how much she likes him; Frankie finds a box of unfinished thank you letters, she orders Axl to finish them, and mail them all out.

Frankie is surprised but relieved when Dr. Goodwin agrees to buy all of the peanut brittle that Brick needs to sell for school. But the good doctor displays a bit of Mr. Hyde behavior when Frankie doesn't deliver the product in an expeditious manner. Meanwhile, Axl is getting sick and tired of having Mike tell him how to run his life; and things go off the rails when Axl attempts to trade in the Winnebago and buy a car. Sue is more determined than ever to win a very prestigious and competitive hotel scholarship; and Frankie swears that she's seeing something mysterious flying through the house.

Frankie has to force Brick into asking Cindy to the high school prom but worries that his quirkiness could spoil the happy event; Lexie talks a clueless Axl into giving Sue a belated 21st birthday present; and Mike becomes frustrated over how to get used to a new TV remote.

In an attempt to get Frankie the best Mother's Day gift ever, Sue and Brick enter a trivia contest where they could win a trip for two to London for the upcoming royal wedding; and Axl is offered a job interview that could change his life.

Frankie makes it her mission to sway Axl from taking the job in Denver; Sue is depressed over Sean leaving for Ghana; Brick buys a huge amount of lawn chairs to replace the one he's been using for nine years.

After nine hilarious and heartfelt seasons, a Heck leaves the nest as the family takes a road trip to Denver, where Axl will start his new job – and new life away from home.

The Hecks find themselves spending New Year's Day attempting to stave off a zombie apocalypse in the Orson Escape Room, desperately trying to beat the Donahue's record of getting out with more than one minute, eight seconds to spare. Meanwhile, Brick is convinced that the mild-mannered man assigned to the family's Escape Room group is really the famous author of the "Planet Nowhere" books; Sue divulges a secret about herself to Axl that's she's been keeping since childhood; and Mike is stunned when Frankie reveals that she had a romantic dream involving Frank Sinatra.

When Mike discovers that Brick is a spelling whiz and won the school spelling bee, he puts all his efforts into training him to win the regional bee, which could ultimately lead to competing in the Scripps Spelling Bee. But as the family gets set for their road trip to Chicago for the regional bee, Frankie and Mike are horrified when they realize they forgot one thing -- Sue's birthday.

As the Super Bowl approaches, Mike is thrilled when Brick takes his advice and studies up on football in order to understand and talk the sport. But Axl thinks his little brother is taking over his turf by being Mike's football buddy - a position Axl used to cherish. Meanwhile, Frankie thinks her professional career is looking up when Mr. Ehlert chooses her to accompany him to a managerial seminar, and ex-boyfriend Brad asks Sue to be his dance partner for the school's annual Square Dancing with the Stars.

Frankie insists that the family go on vacation together before school starts; Mike and Frankie remember their honeymoon, which was ruined by Nicky (Ray Romano), a guy Mike knew in high school.

Valentine's Day aims its sights on the Heck kids when a nervous Brick finds out that his quirky girlfriend Cindy wants him to kiss her on the special day, Darrin asks Frankie and Mike to help out with an exciting scavenger hunt he's putting together for Sue, and Axl begins to question his girlfriend Devin's request that he not give her anything for what she considers to be a lame tradition.

At the annual homecoming tailgate, Frankie worries that her mother will ruin things, Sue takes a familiar role, Axl is sick as a dog, and Mike asks Brick to help him win the cornhole tournament.

Frankie clashes with a coworker at her Thanksgiving job, Sue offers to work to see a guy she likes, Axl has an embarrassing moment at the bar, and Mike and Brick are bored at home after a blackout.

Frankie fears that her innocent flirtation with Axl’s friend has been misinterpreted, and Frankie’s dad, Tag, secretly asks Mike to help him study for his driver’s test so that he doesn't lose his license.

Frankie encounters two perfect siblings and vows to make her children stop fighting and become a loving family. Meanwhile, Aunt Edie makes a costly mistake at the quarry and Mike considers firing her.

Brick pleads with Frankie to leave him home alone when she runs errands.