Harry finds a book. When Ron asks if it is a book, Hermione says that it is "because she knows a thing or two about books". Harry tells them it is not just any book. Ron guesses it's a "young-adult vampire romance novel" (in reference to Twilight), but Harry tells them that he found the book in Severus Snape's bedroom in a locked trunk under his bed. He reveals that the book is Snape's diary. They all agree to read it.
- The first entry is about Snape eating some oatmeal for breakfast, which he thought was "flavorless and watery." He said he thought of his mother and cried.
- The second entry is about Snape getting two mice. One ate the other and died of loneliness. Snape felt "envy."
- The third entry involves Harry and Ron. Harry pointed his middle finger at Snape. Before Snape could punish him with detention, it was said that Harry and Ron (referred to as "his orange friend") shoved him into a wall yelling "bother" over and over (as they did in "Bothering Snape.") That night, he prayed for the first time in twenty years. He prayed for "the end".
- One entry states that Minerva McGonagall pointed out that a button on Snape's cloak was missing.
Button, oh button Oh where hath thou fled? Did thee tarry too long Amongst fabric and thread? Did thee roll off my bosom And cease to exist? How I wish I could follow thee Into the mist...
- Another entry is about Snape falling asleep in the bathtub (EWWW!) and had a nightmare about every thunderclap saying "bother" as he rode a thestral through a thunderstorm and meeting Lily Evans at the Yule Ball. Snape said he asked her to dance, but she asked him to die. He also said that when he woke up, his skin was "prune-like," and he was late for golfing with Lucius Malfoy. After this entry is read, Ron says he liked prunes, and a nude Dumbledore comes up asking if anyone said "prunes".
- The last entry is where Ron drank one of Snape's elixirs, then Argus Filch told Snape he smelled of broccoli and left without saying happy birthday. Snape "thought of his father." He said he cried.
Harry gets bored while reading and writes a new entry. He writes this:
"I am Snape. I'm so sad because I poop my pants all the time. I don't have any friends because I stink like broccoli and poop. And I teach potions to Harry Potter, and it's really boring because he's so cool, and it makes me have depression. Okay, I think I'll go cry now, but not before I poop my pants. Bye."Ron tries to write an entry, but only writes "I AM S" before Hermione cuts him off. Then Snape comes in the room, and finds out about the diary discovery. Harry blames it all on Ron, who tells Snape that he liked the story about the button, and hopes Snape would find it. Snape sheds a tear muttering "So do I, orange one. So do I..." Ron then quietly says "I like buttons!"
An extended version of the episode was released on Twitter. It has an alternate opening, in which Hermione and Ron are wondering where Harry is. Then the regular opening appears. After the part where Snape mentions Argus Filch leaving without wishing Snape a happy birthday, a new part is put in, in which Snape said he spilled coffee on his pants and went to the hospital covering his wet spot. Then someone laughed at Snape and treated the kids' "runny nose." Later Snape said he went to his room, getting a visit from Argus Filch, who punched him in the shoulder and laughed. Then he left. The rest of the original version shows. The oatmeal entry made Ron hungry. He gets some oatmeal from his mom and eats it.