The Tomorrow People - John, Carol and Kenny - have discovered that a teenager called Stephen is about to manifest his powers. They trace him to hospital, where he was taken after collapsing from the shock of his new abilities. Carol teleports into his room to make contact, and begins to teach Stephen how to control his telepathy. They are attacked by Ginge and Lefty, two bikers acting under instruction from the mysterious Jedikiah.

John, Carol and Kenny mount an operation to rescue the kidnapped Stephen. They take him to their Lab, based in a disused part of the London Underground train system, and introduce him to TIM, their biotropic sentient computer. Stephen is still under Jedikiah�s control, and, left alone in the Lab, he deactivates TIM's external connections and opens the door to allow Jedikiah, Ginge and Lefty to enter.

Carol realises that TIM has stopped working and contacts John. They both go to the Lab, but are caught in a trap set by Jedikiah and are stranded in hyperspace. Kenny jaunts to the Lab and manages to reactivate TIM, but Jedikiah burns through the lock of the door, and Kenny is captured. TIM locates Carol and John in hyperspace and jaunts them back to the Lab, but Jedikiah uses a device to paralyse them all.

Jedikiah takes Kenny back to his base, and imprisons him, Ginge and Lefty in a room containing a matter transmitter, which transports them all to a spaceship. Carol, John and Stephen locate Jedikiah's base but only just escape before it explodes. Jedikiah reveals that he is a shape-changing android, working for an alien creature known as the Cyclops. The Cyclops contacts Carol, John and Stephen, telling them to come to his spaceship if they want Kenny back.

John and Stephen jaunt to the ship but are caught in a trap. Carol jaunts to a different part of the ship, and manages to damage Jedikiah with a stun gun. The ship is damaged, releasing John and Stephen. They then find Kenny, and a reformed Ginge and Lefty and release them. The Cyclops explains that his crew has been killed and he needs telepaths to pilot the ship home. As the vessel breaks up, the Cyclops is killed, and the Tomorrow People jaunt back to Earth just before the ship explodes. Jedikiah is left floating in space.

Five hundred years in the future, a spaceship comes across the shape-changing robot Jedikiah, floating in space. The captain, Rabowski, repairs it. In the present day, Stephen is trying unsuccessfully to develop a photograph of something he saw in hyperspace. Carol and Stephen jaunt into hyperspace to see if they can locate anything unusual. Back on the spaceship, Robowski shows Jedikiah his captive, Peter, whose telepathic abilities are being negated by an alien creature known as a Medusa. Jedikiah tricks Peter into operating Rabowski's Time Key, and they travel back to the Tower of London in the present day, and steal the Crown Jewels. When Carol and Stephen jaunt back to the Lab, they find that everyone is frozen.

Carol and Stephen find Jedikiah, Rabowski and Peter at the Tower of London, but Carol is kidnapped and taken back to Rabowski�s spaceship in the future. Jedikiah and Rabowski put Carol into the airlock and start pumping the air out, to force Peter to operate the Time Key again.

Peter agrees to use the Time Key to save Carol, but insists that he be able to use his telepathy to help in the task. Jedikiah lets him, and Peter manages to contact John, Kenny and Stephen, telling them where he and Carol being held. John and Stephen jaunt into hyperspace to look for the spaceship, while Rabowski, Jedikiah and the Medusa use the Time Key to go to the underground tunnels near the Lab. Rabowski captures Ginge, but the biker manages to push the Medusa onto the electrified rail lines, killing it. Ginge is then taken back to the spaceship. John and Stephen find the spaceship in hyperspace, but are shot by the ship�s laser.

TIM brings John and Stephen back to the Lab and, with Kenny, is able to bring them back to life. Jedikiah turns against Rabowski and, in the struggle, the Time Key is damaged. Rabowski makes his way to where Carol, Peter and Ginge are imprisoned, and Jedikiah turns the air and heat off. John and Stephen wake up, have to sleep to regain their strength. Jedikiah restores life support, locks up Rabowski and takes Peter to repair the Time Key. But Peter booby-traps the Time Key, and releases Carol and Rabowski from their cages. Attempting to escape, Jedikiah and Rabowski fight, but are transported by the Time Key to the surface of Mercury. Peter then uses the Time Key to return everyone to their own time zones.

The Tomorrow People are worried by the dramatic increase in natural disasters on Earth. Ginge and Lefty are in Clacton-on-Sea. Ginge meets a girl named Joy, who runs a Haunted House with a man called Smithers. Ginge is kidnapped by Joy, who is working for a strange hooded figure known as the Spidron. Using a matter transporter, Ginge is transported to Spidron�s lair, where he is brainwashed and put to work mining for valuable minerals.

Lefty is worried about Ginge, and contacts the Tomorrow People. Stephen goes with him to the amusement arcade, where they discover the matter transporter in the Haunted House. They are seen by Smithers and Joy. Lefty escapes, but Stephen is captured by Joy and thrown into the sea. John and Carol arrive, but the mysterious man has already rescued Stephen, and teleports Stephen away.

Carol and John go back to the Lab and find Stephen, unharmed. The mysterious man reveals himself to be Steen, a galactic policeman, who is chasing the criminal Spidron, who has been raiding planets for magnamite, a rare substance that holds planets together. Steen, Carol, John and Stephen use the matter transporter in the Haunted House to travel to Spidron's base. Spidron releases all his captives from mind control and opens the lava ducts to flood the base.

Ginge breaks free and closes the lava ducts, while Steen, Carol, John and Stephen find the Spidron's control room, just as he and Joy teleport away. Later, Joy goes to Spidron's hideout near his spaceship, and they prepare to leave Earth with the magnamite. Steen, Carol, John and Stephen track Spidron's spaceship to London, where they find a sewer entrance. Spidron uses mind control on Ginge and Lefty, and escapes alone in his spaceship. Steen arrests Joy, who reveals that she double-crossed Spidron by keeping the magnamite on Earth in the mining areas. When the lava reached the storage areas, the magnamite flowed back into the Earth's crust, stabilising it and averting the destruction of the planet.