|Previous||The Killer Curry|
Sam ask Sally and Doowee to figure out how this happen. They ask Sam a few questions on who could have done it, but found no information. Then, came Jeremy that said that his shirts are shrunk. Sally thinks someone is jealous of their friendship. Sam thinks is Svetlana since she's the president of chess club. However, when Sally and Doowee came they found out all the black spaces are wiped out.
At home, Sally decided to ask the best question to her dad, Harry. After that, Doowee received a call from Albert that all his memories of math is been erased. That made Sally thinks that the culprit is after the presidents. Now, Sally and Doowee decided to come up with a plan.
Devindra, Johnathan, Vanille and Cristelle were called because Sally and Doowee wanted to tell them that the culprit is going after the presidents of each club, so their going to use the camera to see where the culprit is in order to know if it might come after them. Some disagree, but they accept it anyway. However, they didn't find anything.
Doowee then finds out someone has come to sabotage the computer. Sally chased it, but got away. However, Sally found a mint as a clue.
Sally then realized she keeps hearing the word cleaning, so that gives her a idea that the culprit is a cleaning-freak. Doowee thought there's not enough info for a mint, but Sally talks to her pen pal, Anna about more info and she said its made in Japan. Then, they call the number and found out that the serial thief is Cristelle the president of the good manners club because she couldn't stand the mess everywhere of the other presidents of their club. Her punishment is to clean the windows of the school.
In the end, Sally explain things about her pen pal to the class on how she's the professional in cleaning.