Season 1
Episode: 1x01 | Airdate: May 13, 1981
A sudden thunderstorm drives Terry and his sister Helen to shelter in a cave where they encounter another boy, Phil, and are led by mysterious cries for help to Rothgo, a magician from another time, who is trapped in the rock. He commands them to release him and asks them to enter a labyrinth leading to different points in time. He wants them to regain his focus of power, the Nidus, otherwise he will die in the caves as the evil witch Belor, who took the Nidus from him, intended.
Episode: 1x02 | Airdate: May 20, 1981
Terry, Phil and Helen are despatched by Rothgo to another time to recover the Nidus. They arrive in Saxon times where Cynon, High Priest of Druids, gains power from his mysterious sponsor, the beautiful Eliac.
Episode: 1x03 | Airdate: May 27, 1981
Phil, Helen and Terry reappear in medieval England near Nottingham Castle where Belor has created a duplicate Rothgo and Robin of Loxley kidnaps Helen in the belief that she is the Sheriff's niece.
Episode: 1x04 | Airdate: Jun 3, 1981
The children are transported to Arabia where Belor rules as Masrur, the tyrant, and Ali plans a coup to rescue the Caliph. A surprise encounter with Rothgo in the guise of a Grand Vizir leads them to fantastic treasure and the Nidus.
Episode: 1x05 | Airdate: Jun 10, 1981
Rothgo sends the children to the time of Oliver Cromwell. The Nidus seems to be within their grasp, despite a new appearance by Belor as Mistress Wright. The children are mistaken for relatives of Nan Ludd, who shelters them from the searching Roundheads of Colonel Chadwick.
Episode: 1x06 | Airdate: Jun 17, 1981
France is in the grip of revolution and somewhere the Nidus is waiting for the children to seize it for Rothgo. But they become involved in a plot to overthrow the new oppression fueled by Belor in the guise of Juliette, who has already wiped Rothgo's mind.
Episode: 1x07 | Airdate: Jun 24, 1981
The children return to Rothgo in his original labyrinth which he built in Knossos, Ancient Crete as Daedalus. Theseus and Belor, as Ariadne, are also in the lair of the fabulous Minotaur, half man, half bull guardian of the original Nidus.
Season 2
Episode: 2x01 | Airdate: Aug 3, 1981
Armed with new magical powers, Belor rises again from the timeless primeval swamps to torment Rothgo, this time using the Albedo to split the Nidus into fragments throughout time. The old wizard calls on Terry, Helen and Phil for help to save him from destruction in Asgard, the old northern kingdom in the land of the Nibelungs.
Episode: 2x02 | Airdate: Aug 10, 1981
The children are transported to the time of James I, and uncover a very different version of the gunpowder plot. Rothgo is Guy Fawkes, an agent of King James sent to spy on the treacherous Robert Catesby, but doomed to fall foul of Belor in the guise of Queen Anne.
Episode: 2x03 | Airdate: Aug 17, 1981
Having secured one part of the Nidus for Rothgo despite Belor's intervention, the children find themselves in America. Rothgo, as a medicine man, has lost his memory and the children are taken in the besieged fort of Davy Crockett and Colonel Bowie where Belor is at work.
Episode: 2x04 | Airdate: Aug 24, 1981
With two parts of the Nidus already found, the children arrive in ancient India with all its mysticism and magic. But Belor presents yet another unpleasant surprise as she appears as the multi-armed goddess Khumbakarna to foil Rothgo as Prince Sagara, who is due to be married.
Episode: 2x05 | Airdate: Sep 7, 1981
Deep in the sewers of Victorian London, the children encounter an unusual sleuth, T.J. Shadrach, the victim of a spell by Belor to change his face to that of Rothgo as the detective tries to foil a theft of the crown jewels.
Episode: 2x06 | Airdate: Sep 14, 1981
Transported to the Great Siege of Malta in 1565, the children encounter Rothgo in another extraordinary disguise, that of Sir Hugo, an old knight who, with La Valette, tries to keep the Turks at bay.
Episode: 2x07 | Airdate: Sep 21, 1981
The children look for Rothgo in ancient Egypt at the time of Tutankhamun's burial, and seek a final desperate solution to Belor's evil powers. The children are accused of being grave robbers though, and taken before Princess Mertaten.
Season 3
Episode: 3x01 | Airdate: Jul 28, 1982
The evil Belor returns again and Phil, summoned to the caves by a mysterious voice, is lured into Delta Time - an alternative history where fiction exists - by the unreliable magician Lazlo. Lazlo and Phil are soon dying of a disease, and the only hope rests in finding the scarabeaus. Their first trip takes them to Treasure Island and a skirmish with the pirates of John Silver.
Episode: 3x02 | Airdate: Aug 4, 1982
Lazlo, as the incompetant chemist Dr Jekyll, plans to transform himself into the infamous Mr Hyde ... whilst Belor as Mrs Hyde takes control of Victorian London's criminal underworld.
Episode: 3x03 | Airdate: Aug 11, 1982
Phil flies through time to find Lazlo as a seedy priest at the time of the Incas. They search for the scarabeaus in the legendary treasures of the sun worshippers and encounter Belor in the guise of an evil native princess in league with the Spanish Conquistadors.
Episode: 3x04 | Airdate: Aug 18, 1982
Lazlo, as Thomas Farriner, has an angry mob on his heels when his baker's shop begins the Great Fire of London. Belor appears as a countess with magical powers known to the Lord Mayor himself, and seizes Lazlo's bracelet in order to stop Phil finding the scarabeaus.
Episode: 3x05 | Airdate: Aug 25, 1982
Phil and Lazlo, now a ratcatcher, search the catacombs beneath the Paris Opera. Belor poses as a young girl abducted by the fabled Phantom of the Opera and finds the scarabeaus hidden in an unlikely place.
Episode: 3x06 | Airdate: Sep 1, 1982
Phil arrives at the court of Kubla Khan in ancient China. Lazlo, as Marco Polo, struggles to regain the scarabeaus, but is denied posession by a rebellion led by Khan's son, Aybars with some aid from Belor.
Episode: 3x07 | Airdate: Sep 8, 1982
Phil arrives in ancient Britain to find Lazlo in the guise of Merlin, the only one who knows the secret of Excalibur in the days when King Arthur's power is waning in the face of Belor's evil as Morgan Le Fay.