When Lisa's report card reveals that she has failed social skills, she must make a friend in order to bring up her grade.
At school, the kindergarteners play around, while Lisa works with her science equipment. Suddenly, Ms. Shrinivas announces that she's going to give everyone their first report cards. Lisa is given hers and is happy with the fact that she has an "A" in every subject (math, science, vocabulary, etc.). Suddenly, she discovers that she has an "F" in social skills. Lisa asks Ms. Shrinivas if there was an error in printing her report card, but Ms. Shrinivas says that it's not an error. She gave Lisa an "F" in social skills because she hasn't made a friend yet. Lisa tries making a robot called "FriendBot 1000", but Ms. Shrinivas says that Lisa needs to make a human friend in order to bring up her grade.
At the Loud House, Lisa tries to do some research on how friendship works, but eventually decides to settle on observation. She spies on the bondings between Lincoln and Clyde, Lynn and Margo, Lori and Leni, and Lynn Sr. and Kotaro. The next day, Lisa, now using the information she collected yesterday, decides to make friends with the first person who enters the classroom. She rejects the first two students (due to one eating paste, and the other being a biter), but eventually settles on a girl named Darcy Helmandollar. Lisa gets along with her after she compliments on her LED light up shoes, and they play on the see-saw together, provide her with a flavorless dish with all the necessary nutrients, and sleep next to her during nap time. As a result, Lisa's grade in social skills is raised to an "A".
Happy now that her academic record is perfect, Lisa goes back to work with her science equipment. However, Darcy continues to show Lisa her signs of friendship, but Lisa politely declines her offers, showing that she doesn't want to hang out with her anymore. Later, Darcy has made a friendship bracelet for Lisa, but Lisa, no longer able to hold it in anymore, admits that she only became friends with her just so she can boost her social skills grade up, and admits that she doesn't have the time for friends, and gives back the friendship bracelet. Unfortunately, Darcy hurt at realizing that Lisa lied to her, and because Lisa no longer wants to be friends, begins crying and runs off. Lisa, realizing what she has done, tries to apologize, but Darcy has told Ms. Shrinivas what happened. When Ms. Shrinivas offers to read a story to Darcy to make her feel better, Ms. Shrinivas tells Lisa that she lost her "A" again, for hurting Darcy's feelings, and for missing the whole point of friendship. As a result, she sends Lisa to the time-out corner, so she can think about what she has done.
As Lisa sits sadly in the time-out corner and reflects on her now imperfect academic record, Darcy arrives, offering a cookie out of sympathy. Darcy says that she's doing this because Lisa looked sad, and is offering her a cookie to cheer her up since that's what friends do for each other. This statement causes Lisa to learn the true meaning of friendship: it makes your life better. Touched at Darcy's kind gesture, she decides to let Darcy sit next to her, and eat half of the cookie. Ms. Shrinivas, seeing Lisa and Darcy getting along, decides to boost Lisa's grade. Lisa asks Darcy if she would like to come over so they can play with her CAT scanner, and Darcy, thinking Lisa's referring to a real cat, happily obliges.