The Lost Key

Four students at a martial arts academy run by Sifu Faiza are used to training hard, but the lessons also teach them to think clearly, stay calm, and act with integrity. When the school's key vanishes along with the students' karate gear, Joy, Adam, Sam, and Amy find themselves facing a case they must crack themselves. Piece by piece, they lean on arithmetic, working through addition, subtraction, multiplication, and division to decode each clue and trace the culprits.

Along the way, the friends must rely on careful reasoning and teamwork to recover what was taken and locate the missing key.