When Lincoln discovers the first page of his baby book is blank, he worries his parents are hiding something.
Lincoln and Clyde are in the attic, trying to find Lincoln's baby book, because his class is requiring the students to do a report about their birth story, and Lincoln is going to do his the next day. After some digging up, Lincoln finds his baby book, but to his discovery, the page detailing his birth story is blank. Lincoln asks his parents if they know the story, but they both exchange inaccurate information. Thinking his parents are hiding the truth about his birth story, Lincoln and Clyde decide to do some investigating to find the truth.
First, Lincoln asks Lori if she knows his birth story, and Lori says that while Pop-Pop was watching the girls, a scientist came in, holding the infant Lincoln. Lincoln and Clyde admit that it doesn't make much sense, but Lincoln theorizes that he wasn't born, he was made. Digging through his DVD collection, he compares himself to a movie character that was built by a scientist. Despite not having any characteristics of the character, Lincoln and Clyde decide to do a field test. First, Lincoln tries to see if he has super-strength by trying to support a ton of items, but to no avail. Second, Lincoln tries to see if he has super speed, but as he runs, it turns out he's slower than the max speed of Scoots' scooter.
Second, Lincoln and Clyde ask Leni is she knows his birth story, and Leni, claiming she knows it, says that Lincoln was carried in by an eagle. Lincoln realizes that he could be like a character on one of his DVDs that's half human/half eagle. Thinking he doesn't have the characteristics of an eagle, Lincoln and Clyde propose another field test. First, Lincoln tries to see if he can fly, but falls immediately after jumping. Second, Clyde tries to feed Lincoln worms, but upon eating a worm, Lincoln gets nauseous, and vomits nonstop.
Third, Lincoln and Clyde ask Luna, and says that while Mom and Dad were bringing the infant Lincoln into the house, a bunch of men in black surrounded the house. Clyde thinks that Lincoln could be an alien due to one of his DVDs, and once again, propose another field test. Lincoln tries to see if he has alien powers by trying to open the bathroom door telekinetically, but as he tries, Lana opens it at that exact moment. When Clyde says that aliens are able to regenerate chopped off limbs, Lincoln, not wanting to endure that, immediately declares that he's not an alien.
Fourth, Lincoln and Clyde ask Luan, and Luan states that they were expecting another girl. When Lincoln questions why they think they would've had another girl, Luan states that his room was already decorated like a girl's room, and thought they had brought home the wrong baby. Lincoln realizes, that just like a character on one of his DVDs, he might have been switched with another family's baby, and proceed to do some research. After going through all of the birth records, Lincoln and Clyde proceed to investigate on different families to see which one has Lincoln's characteristics.
After turning down a family where the members are tall, a family with rather large noses, and a family with curly red hair, Lincoln and Clyde arrive to a house where the parents have white hair. If that wasn't surprising, they discover that their daughter has hair shaped exactly like Lori's, plays guitar like Luna, and likes spicy subs (just like Lynn). With this information, Lincoln comes to the conclusion that those are his real parents, but decides to have a chat with his quote-unquote "parents."
Back at the Loud House, Lincoln confronts Rita and Lynn Sr., saying that a family with white hair has a daughter that has the characteristics of a Loud, and chews them out by saying that they knew they were going to get another girl, so they paid a doctor to switch babies with another family so they can get a boy. However, Rita and Lynn Sr. laugh at that concept, because according to them, it's false. Rita and Lynn Sr. decide to tell Lincoln his real birth story:
After Rita's water broke, they called Pop-Pop to keep an eye on Lincoln's older sisters, while Lynn Sr. drove Rita to the hospital in Vanzilla. Unsurprisingly, the van ended up breaking down on the side of the road. Just as they were getting worried about Lincoln being born on the side of the road, a black limousine pulled up. Much to Lynn Sr.'s amazement, the President and the First Lady were in the limousine. After explaining their predicament to them, they agreed to drive Rita and Lynn Sr. to the hospital. However, during the course of the ride, it became apparent that they wouldn't make it to the hospital in time for Rita to give birth to Lincoln. The President initially stepped up to the task of delivering Lincoln, but he (along with Lynn Sr.) passed out in the process, so the First Lady stepped up, and successfully delivered Lincoln.
After explaining the story, Rita and Lynn Sr. apologize for not telling their son the story of his birth sooner, because the President was heading to a top secret safe house in Royal Woods that day, and Rita and Lynn Sr. were forced to sign an agreement to never speak of the story to anyone.
Lincoln reminds them of the inaccurate information his sisters provided, such as his room looking like a girl's room, the men in black, the scientist, and the eagle, but his parents manage to clear it up by saying that Lincoln's room looked like a girls' room because they were just using leftover items owned by their first five kids, the men in black were Secret Service agents, the "scientist" was actually the First Lady dressed in equipment from the limo's first aid kit, and the eagle that Leni described was actually a blanket with the Presidential seal on it, given to them by the President and First Lady. Excited about knowing the whole story behind his birth, Clyde points out that this will make a very exciting presentation for Lincoln in class. However, Rita reminds the boys that they can't tell anyone about the story, due to their agreement to keep it confidential.
As Lincoln and Clyde read comics in the former's room, happy that they now know the whole story, Clyde is still perplexed as to why Lincoln has white hair. When Lincoln realizes that he could be just like a character on one of his DVDs, he and Clyde prepare to do another field test.
This is the last episode to air before Chris Savino's firing on October 19, 2017, for sexual misconduct.
There was a popular fan theory in the Loud House community, stating that Lincoln was adopted, because he's the only boy in a house full of girls, and because he has white hair, none of which his sisters have (which he starts to question at the end). This episode, fortunately, debunks that theory, proving that Lincoln is indeed a biological member of the Loud family.
This episode reveals that the First Lady of the United States was the one who delivered Lincoln, and the reason why Lincoln was never informed of this information was because Rita and Lynn Sr. agreed by contract to keep it confidential.
It is revealed that Lincoln has had Bun-Bun since he was a toddler.
It is also implied that Lincoln has had his linen closet bedroom his whole life, because Luan gestured to it when she explained that Lincoln's room was decorated for a girl.
Luna's baby book indicates that she was into music at a very young age, when she actually got into music at 13 years old, as shown in "For Bros About to Rock". It could be possible Luna was referring to rock music, not just music in general.
The fact that the siblings have baby books contradict the events of "The Whole Picture", since it was shown that all of their childhood photos were on the computer. It's possible the photos Lincoln had on the computer were also in his baby book.
On the baby pictures, Lori, Luna, and Lynn's eyelashes are disconnected.
Whenever one of Lincoln's older sisters tell Lincoln the story of his birth...
...Lincoln would compare himself to a character on a DVD he owns...
...Clyde would state "That would explain the white hair."...
...Lincoln would point out a characteristic the character has that he doesn't...
...Lincoln and Clyde propose a field test, and it results in failure.
Rita and Lynn Sr. trying to avoid telling Lincoln his birth story.
When Lincoln and Clyde observe different families...
...they would notice the daughter having a similar trait(s) to one of his sisters...
...but the daughter would have a trait that her parents have that would prove them otherwise, making Lincoln or Clyde remark "Or maybe not."