Greg has been acting strangely of late. This behavior coincides with his mathematics marks plummeting, especially in the fact that he, usually an A-student in math, got an F on his last test. Carol thinks that the two issues may be associated, and perhaps he is sick. When Alice finds a note in Greg's book, they learn that Greg is sick, but not quite the way they had originally thought: he's lovesick, the note being a love letter he wrote to a girl named Linda. Mike and Carol want to help Greg in dealing with his puppy love and by association his lack of focus in math class without letting on that they know about the love letter. This approach doesn't seem to open Greg up to talking about the issue, so they figure they have to find out more about the Linda of his affections. After much searching, they do find Linda, but she's not quite whom they had expected. Ultimately, a friend of Greg's math teacher, Miss O'Hara, may be able to help Greg refocus his priorities back on math.
—Huggo