Jo keeps the promise she has made to her mother and doesn't discuss John Brooke with Meg. Meg can tell that Jo is keeping a secret, but doesn't know what it is.
Laurie can also tell that Meg is keeping a secret. He teases and pesters Jo, and he figures out that it is something about John and Meg, but she still won't tell him the details. He decides to have his revenge with a prank.
Meg seems to have forgotten the matter entirely, although Jo thinks she can detect signs of lovesickness.
One day, Jo delivers the notes from the little "Post Office" between the houses. Meg receives a sealed note that makes her exclaim and blush.
Meg says to herself that it – whatever "it" is – is all a mistake, and "he" didn't send the note after all. She's very upset and blames Jo for something.
Jo and Mrs. March ask Meg to explain. She shows them a note signed with John Brooke's name, confessing his passion for her and asking her how she feels about him.
Jo swears that she didn't write this note or play a trick on Meg.
Mrs. March asks Meg if she answered this first note. Meg says that she did, and that she said that she was too young to think about getting attached, and that she didn't want to hide anything from her parents, and that he should talk to her father.
Mrs. March is pleased with Meg's modest response and tells her that she did the right thing.
Meg tells her mother and Jo that the second note, also signed by John Brooke, says that he didn't send her any love letter and thinks that Jo must have forged it.
Meg is in despair, but when Jo examines the two notes, she thinks that they are both forgeries by Laurie and that John Brooke doesn't know anything about it.
Mrs. March sends Jo to get Laurie. While she is gone, Mrs. March tells Meg that John has asked for permission to court her, and inquires about Meg's feelings.
Meg says that the prank has made her scared and worried, and she can't think about having a lover at this point.
When Jo comes back with Laurie, Meg goes to her room. Jo waits in the hall as Mrs. March spends a long time talking to Laurie, making him realize how cruel the prank really was, and how much mischief it could have caused.
When Jo and Meg are called back into the room, Laurie apologizes to Meg and promises not to tell anyone else about the prank.
Meg forgives Laurie, but Jo doesn't. Laurie is hurt and goes home with his nose in the air.
Jo decides to go over to the Laurences' to tell Laurie that she forgives him. She finds out from the servants that Mr. Laurence and Laurie had a fight.
Jo goes to see Laurie, who tells her that he fought with his grandfather because he couldn't reveal the reason Mrs. March was angry with him – doing so would have broken his promise to Meg not to tell anyone.
Laurie says he wants to run away. For one crazy moment, he and Jo consider running away together and having adventures, and then Jo reminds him that he needs to stay with his grandfather and she has duties at home.
Jo goes to see Mr. Laurence and explains that Laurie has already atoned for his bad behavior, and that he's keeping a secret to protect someone else. Mr. Laurence agrees to trust Laurie and not ask again about what happened.
Jo gets Mr. Laurence to write a note in which he apologizes to Laurie. Jo takes the note to Laurie and encourages him to turn over a new leaf.
Everyone forgets about the prank except Meg, who does start to have romantic daydreams abut John Brooke.