When all 10 of Lincoln's sisters ask him to cover for them on the same day, Lincoln has his hands full.
The story begins with Lincoln and Clyde watching an episode of "ARGGH!", that takes place in a haunted house, where Hunter Spector hunts for a ghost in the bathroom. However, Lincoln realizes that he missed his curfew, and he then calls his sisters, and asks them to cover for him. They do so, and Lincoln makes it home, without his parents knowing he missed curfew.
The next morning, Mom calls the kids downstairs, because it's time for Spring cleaning, much to the kids chagrin. Before Lincoln can start, he is asked if he can cover for Lynn. He agrees, and before he can clean again, Lori and Lily have Lincoln covering for them as well. Then when he is covering for Lily, Leni asks him to cover for her. He agrees, but because Leni was covering for the other six sisters, he must cover for all ten sisters now.
Lincoln manages to make his parents think all eleven of the kids are cleaning, but when Lincoln thinks he has done it, his Pop-Pop wants to talk to all eleven of them, much to Lincoln's shock. Lincoln goes down and says that his sisters were busy cleaning and lies that he was nominated to talk for all of them.
However, Pop-Pop wants Luna to sing him a song. Lincoln calls his sisters and says it is an emergency. While his sisters are on their way home, Lincoln disguises himself as Luna and Luan, and while he is disguised as the twins Luna and Lana show up. They laugh at him for a second before he dresses them up as Leni and Lynn, and the cycle continues as more and more of the sisters show up and need to dress as each other.
Finally, Pop-Pop wants to say bye to all 11 of them as a group. They do this and when they think they've won, their parents see them dressed as one another and demand to know about the situation. They were angry at first, but appreciated that the siblings had each other's back. So they were allowed to go back to their activities if they wore what they were wearing at the moment.
Of course, everyone gets their comeuppance for sneaking out of spring cleaning and they all have a terrible day (especially the sisters). Lincoln claims that he's lucky because all he is doing is watching ARGGH! with Clyde, dressed as Lily, but Clyde invited the whole class, embarrassing Lincoln as the episode ends with him saying Lily's catchphrase.
Luan has no lines in this episode, but was heard complaining with her siblings about having to do spring cleaning, and cheering after their video chat with Pop-Pop. Mall Cop Captain also has no lines in this episode. Lana's friend's voice isn't credited.
The ending where Lincoln's classmates point, laugh at, and record him resembles the opening scene of "Heavy Meddle".
This episode most likely took place after "Making the Grade", since Lisa can see without her glasses.
This episode marks Pop-Pop's first physical appearance; he was mentioned before in "Chore and Peace".
In "Space Invader", Lucy claims that she hates pink. In this episode, she wore Lola's pink dress to cover her.
Although, like Lincoln who dressed up as Lily, Lucy most likely did this to help her siblings.
As of this episode, Lincoln, Luan, Lucy, Lana, and Lily have all had their ears pierced, thus making Lynn and Lisa the only siblings who have never been seen wearing earrings.
Lola is in the Miss Cutie Pie Pageant which Lincoln also tried to win in "Making the Case".
Lori doesn't say "literally" in this episode. Instead, Lincoln and Lucy say it while impersonating her.
In the title card, Lori was using a Lincoln wig, which possibly foreshadows her impersonating Lincoln in a later scene.
Lincoln didn't dress up as Lori, Leni, and Lisa, but he did impersonate both Lori and Leni by talking like them. This makes Lisa the only sister who Lincoln didn't impersonate in any way.
Likewise, Pop-Pop mentions or describes all but one sibling: Lucy.
During production, the sister who would dress up like Leni and do the mirror routine with her was originally Luna, but it was changed to Luan in the final version.
Also, in the scene where all 10 sisters receive Lincoln's text, Lola was in a dance academy rather than a beauty pageant, Luna was with her band playing music, rather than practicing guitar in the garage, and Lori was having the picnic with Bobby near a waterfall.
When Luan is dressed up as Lucy, she has black eye makeup on, implying that Luan has seen Lucy's eyes, and that's how Lucy's eye makeup looks like.
Like in "Picture Perfect", Lana and Lola put marshmallows in their mouths to make it look like they have their two front teeth.
Lincoln got dressed up as...
Luan, which they're both voiced by Marijana Živanović in the Serbian dub
Lynn, which they're both voiced by Sandra de Castro in the Portuguese dub.
Lisa got dressed up as Lancy (hybrid Lucy and Lana), which they're all voiced by Larisa Brokhman in the Russian dub.
Lily got dressed up as Lori, which they're both voiced by Anastasiya Lapina in the Russian dub.
Luna got dressed up as Lynn, which they're both voiced by Natalia Frankova in the Russian dub.
Lola got dressed up as Luna, which they're both voiced by Raquel Ferreira in the Portuguese dub.
Some of the people in Lisa's lecture were cartoon depictions of the writers for The Loud House.
The outfits worn by each of the siblings, and the punishments they each endure with their final outfit at the end of the episode:
Lincoln - Lucy → Lynn → Luna → Luan → Lana & Lola (at the same time) → Lily (Gets embarrassed when Clyde brings their classmates over to the Loud residence to watch ARGGH!)
Lori - Lincoln (Gets humiliated when Lily dressed as her throws up in front of Bobby at the picnic, causing him to faint)
Leni - Lana (Isn't allowed to enter the mall while covered in mud)
Luna - Lynn (Isn't able to play her guitar while wearing Lynn's sports equipment, causing her to break her guitar strings and fall down)
Luan - Leni → Lucy (Scares the children at the birthday party, making her sad)
Lynn - Lisa (Isn't able to hit the baseball while wearing Lisa's glasses)
Lucy - Lori → Lola (Doesn't get taken seriously at the poetry reading and is boo'ed at by the audience)
Lana - Leni (Isn't allowed to play in the mud as a "girly-girl")
Lola - Lucy → Luna (Scares the other girls at the "Miss Cutie Pie" pageant, getting her disqualified)
Lisa - "Lancy" (a combination of Lana and Lucy) → Luan (Gets annoyed when her prop pointer reveals flowers and her squirt flower douses a member of the audience)
Lily - Lori (Vomits after she doesn't receive the necklace Bobby gives her, as it might be a choking hazard)
Lincoln, Luan, Lucy, Lola, and Lisa are the only siblings to dress up in more than one outfit.
Leni and Lana were the only two siblings who were pretending to be each other, while Lincoln, Lori and Lily were the only three pretending to be each other.
Among Lincoln's disguise clothes were some things that don't belong to his sisters:
Pipe (to smoke)
When all 11 of them are finally at the house, they could've change back into their regular clothes, instead of still changing into different outfits.
Additionally, Pop-Pop has a broken sight and didn't use his glasses, this is why he got fooled by the disguises so easily.
Cover Girls - The title of this episode could be an allusion to the makeup brand Covergirl.
The episode's title might also be an allusion to The Cover Girls, a freestyle girl group popular in the late 1980s and early 1990s.
SpongeBob SquarePants - This story has a similar premise to the episode "Overbooked", where SpongeBob has to do favors for Sandy, Mr. Krabs, and Patrick all at the same time.
Duck Soup - Luan and Leni's reaction to being dressed like each other is a nod to the "mirror routine", which was made famous by the Marx Brothers in the 1933 film.
Macarena - The two perform the infamous popular song and dance craze.
Apple - The Loud's computer somewhat resembles an iMac.
On the title card, Lucy is taller than Lincoln.
When Rita says "Linc? Are you okay? We're coming in," the closed-captions say "Ladies, are you okay? We're coming in."
When Lana reads Lincoln's text, the eyelashes from her right eye are missing.
When Lynn is intimidating Lisa and says "Uhh, sofa cushion!" the closed captions read "Soup-for-cookin'."
When the sisters were doing their things, before Lincoln texting them, Luna's eyelashes were missing.
Lincoln texts all his sisters to come home, despite the fact Luna was actually in the house's garage.
However he had the option to text all his sisters at once, so he out of desperation picked this option to make it faster than texting all sisters.
In the Polish dub, during the first conversation with Pop Pop, Lana, disguised as Leni, has Leni's voice and Lynn, disguised as Lisa, has Lisa's voice.
There are several continuity errors as the Loud kids are covering for each other:
Lucy is seen getting dressed as Lola, but is seen dressed as Lori while talking with Pop-Pop.
Lola is seen getting dressed as Luna, but is seen dressed as Lucy while talking with Pop-Pop.
Lisa is seen getting dressed as Luan, but is seen dressed as "Lancy" when she walks away out of Lincoln's room.
Lincoln is seen getting dressed as Lily, but he has his normal clothes when he talks with Lisa about her "Lancy" outfit.
In the first scene of the Loud children searching in the trunk, Lynn has her normal hairstyle instead of Lisa's.
In one scene, Lincoln puts marshmallows on Lana's mouth despite the fact she has already put them before for impersonating Leni.
Luan is shorter than she is when she meets Leni in her disguise as the latter.
When Lincoln was dressed like Lola and Lana, his sideburns change between blonde and white.
When Luna and Lana laugh at Lincoln wearing his half Lana and half Lola disguise, the stripes of the left shoe are red. When Lincoln says "You can make fun of me later!", the stripes of the left shoe are blue.
When the Loud kids are caught by their parents, Lynn's glasses disappear between shots.
Bobby was unaware that Lily was dressed like Lori, yet in "For Bros About to Rock" he knew Luna had disguised herself as Rita.
The stool Lily (as Lori) was sitting on for the final goodbye to Pop-Pop fell over when the kids were caught by their parents, but it disappeared in the next shot.
When the Loud kids' parents are going to Lincoln's room, Lisa and Lily's bedroom door is closed, but then it's open when Lily starts to cry.
When talking with Pop-Pop as the twins, Lincoln has black marker on his incisors, but when Lana and Luna arrived, the black marker has vanished from his teeth. However, when he told them he already has covered them, it once reappears.
If you looks closely, when Lana was imitating Leni, her hair was the same blonde shade as Leni's. But when she was about to play with her friends, her hair was with its normal yellow tone.
Lisa fails to assist Lincoln by telling he has to jump in an angle of 63 degrees, and then corrects herself stating it should be 62 degrees; but since Lincoln hits the house wall in a 63° jump she should've said a 'higher degree measure than 63' rather than saying a lower one.