AllMovie

Coming in at just under an hour, the British The Missing Note was aimed strictly at the kiddie-matinee trade. A cunning jewel thief hides his stolen goods in a beat-up old piano. A group of precocious children come upon the battered instrument, and are fascinated by the fact that one of the keys sticks in a most unusual way. Lo and behold, the kids discover the pilfered jewels, making them targets for annihilation by the disgruntled crook. The best performance is rendered by real-life Regimental Sergeant Major Brittain, here typecast as a police commissioner.