Study Muffin

Lincoln and Clyde are walking home from school, and Lincoln is upset at the fact that he just got an "F" on his latest test. Because of this, Lincoln fears that he will fail the fifth grade. Lincoln realizes that in order to improve his grades, he needs a tutor. At first, he tries to get Lisa to tutor him but Lisa's unable to do so as her tutoring schedule is already filled up. However, still wanting to help her brother, Lisa suggests that Lincoln should get a tutor through the local community college as she claims that students there tutor others to get extra credit for their classes. Lincoln accepts this suggestion and heads off to find a tutor.

Sometime later, Hugh, Lincoln's tutor, arrives. As the two sit down and begin, Lori walks into the room, and inadvertently lays eyes on Hugh. Almost immediately, she swoons over him. Eventually, all the other sisters arrive (with the exception of Lily), and immediately fall head over heels for him. As the sisters and pets (except Geo) begin to crowd around Hugh, Lincoln quickly drags him out.

Lincoln and Hugh try to begin their lessons, but every room they go to the sisters are there, eavesdropping on the two, much to Lincoln's frustration. Eventually, the last place they try to get some progress done is in Charles' doghouse. Unfortunately, the sisters find out about Hugh's location and attempt to enter the doghouse, inadvertently destroying it. Infuriated with his sisters and father, Lincoln calls for a family meeting. Inside the house, Lincoln chews out his sisters and father for their behavior before ordering them to leave him and Hugh alone so that he can prepare for his upcoming test, which they begrudgingly do so.

With the sisters out of the way, Lincoln and Hugh are able to make progress. Hugh discovers that Lincoln is a really smart person, as he's able to know all the answers to his questions. Because of this, Hugh declares that his work here is done, and leaves (by being chased out by Lincoln's madly in love sisters, their British-obsessed father and pets).

The next day, Lincoln comes back from school and is disappointed to learn that he flunked his test again. As Lincoln plops down on the floor in defeat, he unintentionally mentions his substitute teacher's name; Ms. DiMartino. When the sisters hear Lincoln say her name, Luna tells him that Ms. DiMartino is so attractive that all the boys fall head over heels for her. Lincoln explains that Mrs. Johnson broke her leg after riding on a mechanical bull, so she hired a substitute to take cover for her. In a series of flashbacks, Ms. DiMartino's attractive looks made Lincoln lose all of his focus. This makes Lincoln realize that these distractions are what's causing him to repeatedly fail his test. Lisa has the solution: Lincoln simply has to NOT look at her. She proves this correct on Lori by asking her what Bobby's full name is. Lori tries to answer, but Lisa repeatedly shows her the picture of Hugh, causing her to lose her focus and start all over. Lisa then deletes the photo of Hugh, allowing Lori to answer the question without losing her focus. Realizing that it might work, Lincoln heads back to school.

At school, Ms. DiMartino allows Lincoln to retake the test, but this time Lincoln takes the test in his locker to avoid making eye contact with her. After taking the test, Lincoln finally gets an "A". Lincoln believes that he will see Ms. DiMartino in the classroom, so he shields his eyes when he walks in, but to his surprise Mrs. Johnson is back, albeit on a wheelchair.

During gym class, Lincoln is confident that he won't get to see Ms. DiMartino again in another one of his classes. However, it's revealed that Ms. DiMartino will be subbing for Coach Pacowski, whose foot got run over by Mrs. Johnson's wheelchair. Because of this, all the boys immediately get distracted by her attractive looks and run into a pole.