River is dreading the assignment in Mrs. Furley's Human Interaction class. The students actually have to discuss a boy's changes! River is finding it hard enough to figure out how to interact with her own friends. Like, she is happy that D.B. is her sort-of boyfriend, but now Kirstin is always flirting with him. And Margaret and Noah are a good couple, but then Noah passes River a note asking her to call him at home. River never guessed that everyday interactions could get so complicated!