"Evan Treski is people-smart. He's good at talking with people, even grownups. His younger sister, Jessie, on the other hand, is math-smart--but not especially good at understanding people. She knows that feelings are her weakest subject. With just five days left of summer vacation, Evan and Jessie launch an all-out war to see who can sell the most lemonade before school starts. As the battleground heats up, there really is no telling who will win--and...

Evan and his younger sister, Jessie, react very differently to the news that they will be in the same class for fourth grade and as the end of summer approaches, they battle it out through lemonade stands, each trying to be the first to earn one hundred dollars. Evan y su hermana menor, Jessie, reaccionan de manera muy diferente a la noticia de que van a estar en la misma clase de cuarto grado y como el final del verano se acerca, ellos luchan hacia...