When the toilet is discovered to be clogged again, everybody points their fingers at Lincoln, since he has a habit of clogging the toilet. Wanting to prove he didn't do it this time, he, along with Lucy, go on an investigation to find the true perpetrator.
Lincoln is preparing for a comic book convention about superhero Ace Savvy, but when he prepares to use the bathroom, toilet water comes flooding out, showing that someone had clogged it last night. The girls thinks Lincoln did it, as he has a habit of doing so, but he protests that he didn't do it this time. As usual, Lola tells Dad about it and he announces that they're all grounded until the perpetrator is found out.
With his trip to the convention in jeopardy, Lincoln decides that he has to find the culprit and Lucy willingly joins him in the mystery. First, they go to Lynn as she has eaten a lot of sub sandwiches the previous day, but she claims that she didn't do it since she believes that going to the bathroom is bad luck for her favorite roller derby team. Lynn suggests that they go see Lisa, who keeps a record of the family's toilet habits in a filing cabinet. Lincoln and Lucy find that the document for who used it between 1:00 AM and 4:00 AM is missing, making them suspect that is was Lisa, but she's vindicated when she admits that she prefers using Lily's training potty. They then suspect Lily since she's always throwing her diapers in the toilet, but she's proven innocent when Lincoln knocks over her diaper genie and spills out its disgusting contents. Lincoln then suspects Lori since she was the first to blame him for clogging the toilet, but an atomic wedgie from her convinces him otherwise.
Lincoln and Lucy try to get the truth out from the rest of their sisters, but all prove themselves innocent; Luan says that she was asleep at the time (which she proves by revealing that she records herself in case she makes a good joke in her sleep), Leni is too dumb to have done it, Lana says she's tried and failed countless times to clog the bowl, Lola says she would never get up to interrupt her beauty sleep, and Luna says she was at a rock concert that night (which she proves by showing a TV report showing herself crazily chasing Mick Swagger onstage so she can get a lock of his hair).
Meanwhile, Dad and Lana are fixing the toilet with the plunger "Big Bertha" where Lana discovers what clogged the toilet: a book titled Princess Pony, making Lincoln suspect Lola of being the clogger. He and Lucy go into her room to interrogate her, but she claims that not even she would read something so sickeningly sweet as that. Just then, Clyde arrives at the front door and hands Lincoln a page from the Princess Pony book (which Lana had thrown out the window earlier). Reading a quote from the page, Lincoln discovers that Lucy had said the exact same statement while interrogating Lola earlier, making him suspect that Lucy is actually the culprit.
Lincoln enters Lucy's room to get her to confess, but she denies being the reader. After a search through the premises, Lincoln finds Lisa's missing bathroom file in the overhead lamp and a poster on Lucy's wall flips down to reveal a Princess Pony poster behind it. Lucy confesses that she was the reader, something she tries to keep a secret from her sisters. She also reveals that the toilet got clogged when she tried to read it in the bathroom late at night. She hid it in the toilet when a half-asleep Lincoln came in to use it and he flushed it unaware that the book was in it. Lincoln demands that Lucy tell the girls the truth, but Lucy is nervous about it since they'll tease her more than they do him.
Lincoln and Lucy come downstairs to reveal to the girls the Princess Pony book that clogged the toilet, and they proceed to mock the book and vow to make whoever owns it a laughingstock. Just as Lucy prepares to confess that it was hers, Lincoln, feeling sorry for Lucy, claims that the book is his and takes the blame for clogging the toilet. As a result, Lincoln gets grounded, and the girls are ungrounded, forgoing his chances of going to the convention.
Lucy asks why Lincoln took the blame, and Lincoln says he's comfortable with himself, and he has Lucy's back. Grateful, Lucy thanks her older brother for keeping her secret from the others. Later that night, Lucy cheers Lincoln up by presenting him with a creepy comic book she drew as thanks for helping her. The episode ends with Lynn going to the bathroom to relieve herself after winning the game and Lana calling for Dad to get Big Bertha again.
This episode, alongside "Hand-Me-Downer", was released on Nick.com and other digital platforms on April 15, 2016, ahead of its television premiere.
According to the episode writer, Whitney Wetta, the inspiration for this episode came from her childhood, when her older sister, who often clogged the toilet, would always pin the blame on Whitney, and her family would believe her, because she was the oldest. When New Year's Day was approaching, Whitney found in her sister's diary that one of her New Year's resolutions was to stop blaming her younger sister for clogging the toilet, and Whitney showed this diary entry to her parents as proof that the older sister was the one responsible for all the toilet clogs in the past.
The APM track "Caped Crusader" is prominently heard throughout the episode.
It is used in some episodes of SpongeBob SquarePants, another popular Nickelodeon show, particularly in the Mermaid Man and Barnacle Boy episodes.
This marks the second time a track from SpongeBob SquarePants is used on the show, the first track used was "Vibe Link (b)", which is heard in several episodes.
The episode's dialogue has a lot of alliteration, a chain of words that start with the same letter and sound, when referring to the toilet's clogging.
Lincoln dressing up as Ace Savvy and Clyde as One-Eyed Jack is an act of the real life concept of cosplaying- dressing up as a character from a franchise they are fans of.
Lynn has the following books on her desk: "Amazons" and "Sport Statistics 1897-1999 Slow Jump".
Not counting the flashbacks of him clogging the toilet, Lincoln doesn't wear his usual outfit throughout the whole story.
Episode 10 of Season 1 is the first episode where Lily does not have any lines of dialogue in either of the segments she appears in.
Moral: Always help out a family member, even if it means sacrificing something you like.
After "Undie Pressure", since Lincoln used his victory undies in this episode.
Before "The Whole Picture", since Lincoln used the same Ace Savvy costume in that episode.
Sleuth or Consequences - The title is a parody of the game show Truth or Consequences.
Spider-Man - Clyde's "One-Eyed Jack" song is a parody of Spider-Man's theme song.
My Little Pony - Princess Pony is an obvious spoof of the toy franchise.
Batman - The title card features Lincoln making the Batman pose in the dark only showing a silhouette of him.
Possible: When Lincoln's sisters first glare at him after accusing him of clogging the toilet, Leni's arms are crossed. However, when Lola brings their Dad up, her hands are on her hips. She may have just changed the position of her arms.
When Lola tells Lucy that she wants her to clean up the mess she made in her room, her gloves are the same color as her dress.
Lana laughs alongside her sisters when Lucy reveals the Princess Pony book that clogged the toilet, despite the fact that she pulled it out, meaning she already knew about it.
Right when Lincoln finishes saying "Your big brother's got your back", his teeth line changes to a traditional teeth line (black vertical stripes) like the others instead of his chipped buck tooth on top of a white solid background.
When Lana said "Big Bertha coming through!" while entering the bathroom, her eyelashes are gone.
Before Lynn eats her meatball sub, her eyelashes are gone.
When the sisters are laughing at Lincoln's Ace Savvy costume, Lynn and Lana's eyelashes are missing.
Lola telling on Lincoln every time he (most of the time) clogged the toilet.
Lincoln kicking doors open.
Lincoln failing to do card tricks.
Lincoln and Lucy interrogating their sisters.
Lincoln's sisters being inconsiderate towards him.
Road Tripped • Hide nor Hare/Geri-antics • Roadie to Nowhere/A Fridge Too Far • Selfie Improvement/No Place Like Homeschool • City Slickers/Fool Me Twice • Net Gains/Pipe Dreams • Fandom Pains/Teacher's Union • Rita Her Heights/The Mad Scientist • Head Poet's Anxiety/Missed Connection • Friendzy/Deal Me Out • Pasture Bedtime/Shop Girl • Gown and Out/Breaking Dad