"Lock 'N' Loud" is the sixty-fourth episode of The Loud House.
When Dad gets upset with his kids for never locking the front door at night, they decide to take home security to the next level, and end up overdoing it.
Late at night, Rita and Lynn Sr. arrive back home after taking ballroom dance classes. After Lynn Sr. inadvertently twirls Rita into a rose bush, he heads into the house to get a first aid kit, but to his frustration, he opens the door without having to unlock it. He enters the house and scolds the relaxing kids for not locking the door at night. When Luna questions what the big deal is, Lynn Sr. explains that there have been some burglaries recently, and fears that their house might be next. After Lynn Sr. locks the door to show how easy it is, the kids go back to relaxing, but Rita's still trapped in the rose bush.
In Lori and Leni's room, Lincoln points out to his sisters that their dad's right in that they need to be more responsible if they don't want their house to get robbed. As the sisters hug what they don't want to lose, Lincoln states that just locking the front door isn't enough if they want to protect their stuff. They decide to lock down the whole place, which the sisters cheer to, including Lily, who yells out a triumphant "Ga-ga!", and holds up toy keys in her hand.
Clyde arrives at the Loud House, but before he can walk onto the porch, Bobby, on a Segway while wearing his mall police attire, approaches Clyde and asks him for his name and business. When Clyde asks Bobby what he's doing, the latter informs that due to new security measures by Lori, he was hired to guard the house. Lori decides to vouch for Clyde, and he's allowed access into the house. The moment he steps in, he falls victim to two of Lisa's alarm systems, and flees before she unleashes a third one (an alligator pit). Clyde enters Lincoln's room, ready for the job. After drinking some coffee that Clyde brought for them (which they end up not liking), the scanner informs them about an 11-25 (which, according to the Royal Woods Police Codebook, means failure to pick up dog poop).
When Lincoln exits his room, he witnesses his sisters stashing their closest possessions in the bathroom. When Lincoln questions Lisa why the bathroom is the chosen location, the latter states that she had cameras installed in the bathroom since last year. When Lincoln is about leave, he hears Lynn shout out that there is a burglar present. When Lincoln checks up on Lynn, it turns out she's just trying to teach Leni and Lola how to attack the burglar. While Leni fails miserably due to finding the dummy cute, Lola viciously attacks it after Lynn tells her to pretend that it had stolen her pageant-tiaras. When Lincoln walks into the kitchen, he notices a hooded figure entering from the window. The figure turns out to be Lana, who explains to her brother that she's trying to teach Charles to be a vicious guard dog. However, Charles is too lazy to do Lana's commands.
Later that day, Rita and Lynn Sr. are about head off to dance class again, but not before Bobby stops them to ask them for their names and business (only to unintentionally state them himself). Sometime later, as Lincoln and Clyde are sleeping, the scanner goes off and reports a 10-15. As Lincoln checks the codebook, a 10-15 means that the burglar has been caught. As Clyde and the Loud kids begin cheering at this, Rita and Lynn Sr. arrive back home. After Lynn Sr. once again twirls Rita into another predicament, he prepares to enter the house, only to once again, finding it unlocked. As the kids take back all of their possessions, Lynn Sr. once again scolds the kids for not locking the front door. When Lincoln informs him that the burglar has been caught, Lynn Sr. points out that there could be other burglars out there, but the kids pay little heed--Lisa even points out that the chances of there actually being more criminals is statistically unlikely, especially with how low of a crime rate Royal Woods has. Lincoln also explains that he had been listening to the city's police scanner all day, and the worst crime he heard about was somebody simply forgetting to pick up dog poop. Lynn Sr., fed up, goes downstairs and locks the door himself, once again forgetting to help out Rita.
The next night, Rita and Lynn Sr. once again leave for dance class, but the instant they leave, Mr. Grouse yells out that he has been robbed. When the Loud kids check up on Mr. Grouse, the latter informs that several of his closest possessions have been stolen. Fearing that the (other) burglars could attack their house next, the kids decide to take their security to the next level. After stashing their possessions in the bathroom again, the kids prepare to do some improvements, which include: Lincoln and Clyde filling a vat with bacon grease; Lola operating a searchlight; Luna, Lucy and Lily digging a ditch surrounded with barbed wire; Luan setting up numerous mousetraps; Lynn recruiting her roller derby teammates to work alongside Bobby. When Rita and Lynn Sr. arrive back home, they're shocked at how far the kids are taking this. While Lynn Sr. admits that he appreciates that the kids are taking it more seriously, he feels they've taken it too far and makes them go to bed.
Later that night, a shadowy figure comes out of the Loud House and approaches Mr. Grouse's house, and knocks the door. The shadowy figure is revealed to be Lynn Sr., who had Mr. Grouse pretend that he was robbed so he can teach the kids a lesson. After paying Mr. Grouse with a basket of muffins, Lynn Sr. prepares to head back into the house. Leni, after grabbing a glass of milk from the fridge, hears a twig snap outside. She peeks out the door, and seeing nobody, closes it and locks it. Realizing he got locked out, Lynn Sr. tries to climb through the kitchen window, but it turns out to be locked too. When Lynn Sr. falls over (due to standing on a tricycle while struggling to open the window), his noisiness catches the attention of Lincoln. He peeks through his window, and witnesses a shadowy figure below. Thinking it's a burglar, Lincoln pulls on a string that rings a bell in everyone's bedroom, waking them up and telling them to take action. As Lynn Sr. tries to find another way in, he falls victim to the kids various traps, such as Luan's mousetraps, Lincoln and Clyde's vat of grease, the ditch that Luna, Lucy and Lily dug and Lynn's roller derby teammates pummeling him.
Rita orders the teammates to stop attacking, since she recognizes the dance shoes present. When it is revealed to Lynn Sr., he lies by saying that he was out for a walk and he got locked out. As everyone apologizes to him for attacking him, Mr. Grouse, his face incredibly swollen, complains that the muffins Lynn Sr. gave him have walnuts (which Mr. Grouse is allergic to), and warns him that if he ever wants to pay him for pretending to be robbed, he should give him something he's not allergic to. With the beans spilled, Rita and the kids get mad at him for lying to them and for wasting their time on securing the entire house for nothing. He apologizes, explaining that, along with reminding his kids to lock the door, he was doing it ultimately to protect his family. Rita and the kids are touched by this, and forgive Lynn Sr. As Rita and the kids are hugging him, Charles notices a couple of bacon strips stuck to Lynn Sr.'s butt, and advances towards him. Charles bites down on Lynn Sr.'s butt, causing him to cry out "OUCH!" in pain, and Lana (sarcastically) remarks "Finally!", due to Charles doing exactly what she wanted him to do.
Margo and three of Lynn's roller derby teammates have no lines in this episode.