The quads accidentally force out the easy-going gym teacher after Ricky tripped him, ruining the class for everyone; he, Nicky, Dicky and Dawn think they've fixed everything with the perfect substitutes, but soon realize their parents have made things worse.
During a P.E class at Edgewood School, the Harper Quads keep complaining about how much they can't stand gym. Coach Fessler comes in and complains that the kids are not even doing jumping jacks properly. The coach is disappointed when Harpers complain to the coach that gym is awful. Ricky even comes up with fake stats to convince the coach that physical exercise isn't worth it. The coach asks the rest of the kids if they want to "flitter" like the Harpers are suggesting or if they want to do actual physical activities. After a short hurdle, Dawn announces that they choose not to do anything. The coach gets mad and tells them to do whatever they want. He's given up.
The kids see this as victory but the Harpers quickly ruin it again when Ricky and Dicky get the coach injured while messing around with a skateboard that has rockets attached to it. The coach is taken to the hospital but now Principal Tarian must find another coach. He suggests getting Mr. McGee as a substitute P.E. teacher but the entire class hates him because he was so tough on them. Miles complains that they will never survive "Pull-Ups McGee." Natlee blames the quads for giving them flittering and then taking it away. Mae sides with the rest of the students against the Harpers. Dawn promises to fix things but Trey says that he has a list of the many times that the quads let the class down.
In order to fix things, the Harper Quads get into Principal Tarian's office before he makes the call to Mr. McGee. They urge him to hire a different substitute so that the students can get variety. Tarian goes to the list of substitutes and the first in the list is Tom Harper. This makes Anne jealous and mad because Tom cheated by entering his name in the list as "Aaamazing Tom." The Harpers convince Tom to let the kids kick back and chill. This makes the Harpers' classmates very happy.
However, while the kids are sitting idle in the gym, Tom starts telling them embarrassing stories about Dawn and her brothers. So, the quads start looking for ways to get rid of their father. The quads ask their dad to stop but then he starts making them all play "Meow-Meow," an embarrassing game the kids used to play. He even makes the whole class play the game, making them mad again at the Harpers. The quads can't take this anymore. They complain to their mom about it.
So, Anne encourages them to get their dad fired. The Harpers convince Principal Tarian to fire Tom by lying that he said turtles are a stupid pet. But Tarian loves his pet turtle, Shelly. So, he fires Tom and hires Anne as the next coach. Things with Anne as the coach don't go so well because the boys in the class all develop crush on Anne, calling her "smoking hot." They keep giving her presents which get the Harpers grossed out.
Realizing that their parents are only making things worse, the Harper quads decide to go back to the hospital to visit their original coach and beg him to return. On arrival, the nurse tells them that it's too late. The coach has gone to the big gym upstairs. The quads conclude that the coach is dead. They start talking about how sad they are to lose their coach and how they wish they told the coach that gym is important. While they're still talking the coach enters the hospital ward on a wheelchair. He overhears everything. When he finally talks, the quads at first think he's a ghost. He reveals that the "big gym upstairs" is literally a big gym upstairs.
The quads beg him to come back to teach the class by admitting that physical education is important and that he's the best teacher they've ever had.
While celebrating, the quads accidentally launch the coach's wheelchair causing him to fall through the window. They rush to hold it from falling.
- Lizzy Greene as Dawn Harper
- Casey Simpson as Ricky Harper
- Mace Coronel as Dicky Harper
- Aidan Gallagher as Nicky Harper
- Allison Munn as Anne Harper
- Brian Stepanek as Tom Harper
- Kyla Drew Simmons as Mae Valentine
- Siena Agudong as Natlee
- Theodore John Barnes as Miles
- Jason Sims-Prewitt as Principal Tarian
- Spencer Tomich as Trey
- Spencer Tomich as Coach
- Christine Lin as Nurse