The Mighty Atom is an amazing surveillance device which to all intents and purposes looks like a small mouse. In actuality, it incorporates a powerful concealed minature camera that can penetrate installations undetected and photograph control systems by focusing on the technician's faces as they monitor the control panels.
As a safety factor, if the mouse is seen or approached, it runs for the nearest cover and hides like a real mouse.
The Hood under the disguise of Professor Langley had been invited to a demonstration of the "Mighty Atom" at a Government research unit. He used his hypnotic powers to overcome the demonstrator (Professor Holden) and the other guests, and then stole the device to photograph the control room of the new Irrigation plant built in the Sahara Desert.
He plans to lure International Rescue and use the Mighty Atom to photograph the control cabins of the International Rescue craft, by setting off a fire in the manner of the one at the Australian plant.
When Thunderbird 2 arrives at the scene of the fire, on board is Lady Penelope Creighton-Ward who had begged Jeff Tracy to let her go along on the mission. The Hood sends in the Mighty Atom to photograph the controls but is furious when he later discovers that the robotic mouse has instead taken pictures of Lady Penelope screaming at it because of its programming causing it to focus on photographing a moving figure rather than the immobile control systems.
In anger, the Hood then destroys the device.
- The Mighty Atom is programmed only to photograph the profiles of the human faces, yet we see it taking photographs of the control panels at the Saharan Atomic Station when no one is in the room.