After secretly reading Luna's diary, Leni and Lincoln become worried about the exploits their sister writes about.
While Lincoln is playing video games in the living room, Leni arrives, looking for a new chapter book to read after Lily took hers to make a book fort. While looking under the couch, Leni finds a purple book with a guitar, and upon reading the names listed (which include Luna, Luan, and Lincoln), Lincoln discovers that Leni found Luna's diary. For the sake of her privacy, they suggest that they put it back in its hiding spot, but the two are tempted to read what Luna's big secret is. However, before they could read any further, Luna arrives, prompting them to hide the diary, and upon entering, Luna takes her diary from her hiding spot and heads upstairs. Now more desperate to find out what Luna's big secret is, Lincoln and Leni resolve to find out.
The next day, Luna heads out to band practice with Sam, and Leni, under the guise of picking up laundry (with Lincoln hiding in her basket), sneaks into Luna and Luan's room to find the diary. Suddenly, Luan enters and interrogates Leni into revealing why the two are sneaking in their room. When Leni says she and Lincoln are trying to find Luna's diary, Luan is appalled that they're trying to invade her privacy but is tempted to look by Mr. Coconuts. After some searching, Leni finds the diary under Luna's bedsheets and reads that her big secret is that she skipped school to see a movie with a girl named Roxy. Thinking that Luna is becoming a bad girl, the three decide to keep a close eye on her.
Throughout the days, Lincoln, Leni, and Luan learn more secrets about Luna, like how she got a tattoo on her ankle and sneaked to an underground club with Roxy instead of studying for finals. While spying on Luna from Lori and Leni's room, Luan enters and says that the latest entry in the diary reveals that Luna and Roxy are planning a night of mayhem in Royal Woods, where they plan on filling the fountain with nacho cheese, release all the goats at the petting zoo, start fights at a biker club, and steal the "R" from the Royal Woods Town Hall. Wanting to save Luna from being a bad influence, the three decide to foil their plans.
Later that night, Lincoln, Leni, and Luan, donning ninja suits, attempt to beat out Luna and Roxy at their intended destinations. Traveling by bike, they first arrive at Flip's Food and Fuel, where they proceed to buy all of his nacho cheese. Next, they arrive to the petting zoo and attempt to relocate the goats into a nearby barn. When the goats suddenly run rampant, Lincoln quickly calls Liam and tells him that the goats just need something to lure them, so they use the cheese, and hide them just as Luna and Roxy arrive. Next, they arrive at The Biker Brawlhouse, the biker club where Luna and Roxy are expected to start fights. The three decide to shut off the sign, but the bikers chase them away for turning it off (and for Luan insulting their body odor).
Lastly, they head to Royal Woods Town Hall, only to find out that Luna beat them to it and is preparing to take the "R" off the building. When they spot a security guard making the corner, the three come out to warn Luna, and ultimately confess that they read her diary. Luna is understandably furious that they invaded her privacy, but Lincoln, Leni, and Luan were only trying to help her from becoming a bad person growing up. Suddenly, Luna laughs, revealing that she actually knew they were reading her diary. She explains that on the day Lincoln and Leni found the diary, one of Leni's strands of hair was stuck to it and overheard the two stating that they read it. This gave Luna the idea to write fake stories in order to mislead them, and her and Roxy's "night of mayhem" was entirely a ruse to get them to confess, with Roxy revealed to be Sam in disguise the entire time.
With everything revealed, Lincoln and Luan apologize for doubting her, and Luna apologizes for the trouble she put them through, but the moment is cut short when the security guard patrolling the building (who is actually real and not an actor Luna hired as Leni had mistaken) chases them off. After escaping, Mr. Coconuts attempts to ask Luna what her big secret really is, but Luna, annoyed and not wanting to tell, throws him in a garbage can.
During the initial airing of this episode, the viewers had the chance to answer trivia questions related to the episode with the Nickelodeon Screens Up app or on Nickplay.com for a chance to see their name on screen.
What does Leni find under the chair?
Luna's diary and a Sock
Luna's diary and a Purple Donut
Luna's diary and Geo
Luna's diary and a Green Bagel
What day is laundry day?
Luna's diary says she skipped school to...
See a slasher flick at the mall
Give a smasher kick to a ball
See a rock show
Luna's diary says she finally got a...
Mick Swagger autograph
Brand new guitar
Luna's diary says she and Roxy want to fill the fountain with...
Who tastes the nacho cheese?
What's the name of the biker bar?
Open for Badness
Bikes for Tikes
The Biker Brawlhouse
The Biker Brawlpit
Lucy House 024
Shadow Prodigy 029
Luna Buddy 026
LENI WATTERSON 001
This episode reveals that laundry day at the Loud house is on Tuesdays.
The band Luna "snuck out to" is Q Bomb, which former background designer Gene Goldstein is apart of.
The person who is thrown out of the biker club was Kyle Marshall.
If one looks closely as Lincoln, Leni and Luan ride away from the bikers, Mr. Coconuts can be seen moving on his own without Luan controlling him (as she's using both of her hands to hold onto her bike handles). Whether this is part of his somewhat sentience from episodes like "Stage Plight" and "A Pimple Plan" or an error is up for debate.
At first, Lincoln, Leni, and Luan were unsure what to do with the cheese they got from Flip but learned it was useful for them to lure the goats into where they wanted them to go.
Luan first scolds Leni and Lincoln for reading Luna's diary, but she decides to read it later too.
Foreshadowing: Three subtle hints that give away the fact that Roxy was Sam in disguise were the piercings on her ears, the skull on the back of her jacket, and the dark purple jeans.
Snoop's On - The title of this episode is a play on the phrase "soup's on", meaning that a meal is served.
Naruto - Ninja outfits used by Lincoln, Luan and Leni have metal forehead protectors like in this manga series.
The square title card mistakenly omits the apostrophe.
Leni's line "Hey!", is said in Luan's voice.
When Lincoln and Leni are panicking as Luna is about to enter the house, the coloring of Luna's diary is darker than usual.
Throughout the episode, the bookmark on Luna's diary keeps disappearing and reappearing.
Possible: Upon closer inspection, as Luna is getting her diary from under the chair, even in the flashback, there's nothing on it. But when Luna gets upstairs, she finds a lock of Leni's hair, which suddenly appears on the diary. It's possible it was hidden so that the audience wouldn't be aware that Luna knew all along that Lincoln and Leni read her diary all along.
When Sam (Roxy) takes off her wig, the wig's back part disappears for a second and then appears back.
Possible: When Luna said "Gonna go jam with Sam", her right paperclip earring is not in her ear.
When Leni hold the photo frame in front of her head, She has only two pairs of eyelashes and they are disconnected.
When Luan and Lincoln are stopping Leni, Lincoln's front tooth are wrong.
When Luan wakes up and sees Luna sneaking back in, Mr. Coconuts is missing the blush on his cheeks.
After the flash forward of the mayhem and Lincoln says "Trespassing?", Luan has her phone in her left hand. In the next shot, Luan's phone is in her right hand while Mr. Coconuts is in her left hand.
When Mr. Coconuts is wearing a ninja costume, his nose is not seen. At the biker club, when he is sniffing the bikers, his nose is sticking up from his mask. Then at the end of the episode, his nose is shown.
In the flashback, the way Luna holds her diary when getting it from under the chair is different from when she was holding it in the beginning. Also, her diary flips sides between shots when she's going upstairs.
In the Latin American Spanish dub, when the kids see the cop in the Hall, Mr. Coconuts doesn't have his voice, instead, the normal voice of Luan sounds.