When eighth grader Tess looks at the back wall on the church across from her school, she notices something that she's never noticed before: about twenty bright green fours. Her friend gives her the idea that maybe, just maybe, the fours mean something. With this in mind, and being the math whiz that she is, Tess decides that maybe they are a fours four problem (a type of math problem) and decides to figure it out and look for a pattern or a code. Throughout the next few days, she gets help with the problem from her friends and a boy that she really likes, who keeps waiting for her after her school clubs. Does that mean that he likes her too, and if so, will they be able to take their relationship to the next level? Will she ever be able to stop the harassment from Richard, a classmate, who is cruel to her because she was going to tattle on him for stealing the answers to the U.S. Constitution exam? Also, will she ever find out what the problem means? Find out by reading Writing on the Wall.