While playing Hide-and-Seek, Terry and his sister, Helen, are caught in a sudden thunderstorm; however, on taking refuge in a nearby cave they are surprised to find that they are not wet. Inside the cave Terry and Helen encounter Phil, an older boy who has been following their recent game. After hearing a strange voice calling for help, the three children decide to explore the tunnel system; they soon reach a large cavern, where they find a black-dressed man trapped under a huge rock. The stranger gives his name as Rothgo, explaining that he is a wizard who has been imprisoned by his enemy, an evil witch named Belor. Rothgo urges the children to join hands and concentrate, and, to their astonishment, the stone levitates, allowing the wizard to get free. Rothgo implores the children for help: Belor has stolen from him a mystical object known as the Nidas, and hidden it somewhere in the past; without the Nidas, Rothgo is incomplete, and he will soon die – however, if the children will agree to help retrieve the object, his powers will be restored. Helen and Phil immediately agree, and, together with a hesitant Terry, they step into a magical stone labyrinth that transports them back through time and space…
Travelling many centuries into the past, Helen, Terry and Phil arrive in a cave at the time of the Winter Solstice; here they encounter an old druid who appears to be Rothgo, but whose memory has been scrambled by a curse. On seeing Phil’s black skin the druid instantly proclaims the boy to be ‘the dark warrior’ who it is prophesied will challenge Cynon, the spoilt tyrant who has usurped Rothgo’s throne as high priest of the druids. However, Cynon’s sponsor is an evil woman named Iliac – who is in fact Belor in disguise; when she recognises the children Belor quickly traps them inside a cave, while her future self seeks out Rothgo and engages him in a deadly battle in the night skies. But Rothgo is able to stall Belor, allowing the three children to escape, say his name, and restore his past self’s memory. With Rothgo’s help Phil must now challenge Cynon – but will he be able to best the powerful dictator and discover the location of the Nidas..?
Helen, Terry and Phil travel back seven-hundred years, arriving in the dungeon of the Sheriff of Nottingham. While Helen is abducted by a mysterious robed figure, Terry and Phil are captured as Saracen spies and imprisoned in a cell, where they meet a magician who appears to be Rothgo; however, the boys are unaware that the man is merely an illusion created by the Lady Eleanor – Belor in disguise. Helen learns that her captor is an aging Robin of Loxley, who was formerly known as Robin Hood; it seems that Robin mistook Helen for the Sheriff's niece, Rowena, whom he hoped to exchange in return for his medallion; this mystical object was stolen by the Sheriff, and its loss has caused Robin to lose his faith in himself. Helen suspects that the medallion may be the Nidas, and so she agrees to help Robin recover it in return for finding her friends. Meanwhile, Terry and Phil have been completely taken in by the fake Rothgo; the trio are released by Lady Eleanor – but only so that ‘Rothgo’ can lead the boys into a trap...
Arriving in the mystical Far East, the children contact Rothgo for advice; the magician has rested, and is now able to grant Helen the power to free anyone imprisoned by “Masrur”. Exploring the caverns the trio soon find a man imprisoned inside a large water jar; after Helen releases him, the self-proclaimed Ali the Defender explains that he had been imprisoned by Masrur, an evil sorceress who has taken over the land after capturing the Caliph and forcing the Grand Vizier to flee. Terry, Helen and Phil immediately suspect that Masrur is Belor and the Grand Vizier to be Rothgo, but before they can act, they are confronted by guards sent by Masrur; Ali escapes, but the three children are trapped in the Chamber of Fire, where they are choked by deadly sulphurous fumes. Luckily the room also contains the imprisoned Vizier, and once Helen speaks his name, Rothgo awakens and disperses the toxic gas – much to Masrur’s fury. Elsewhere, Ali learns that his army of men have all deserted him, except for one loyal follower, Ahmed; Ali vows to stop Masrur, but it seems that his motives centre around himself rather than his people. Meanwhile, Rothgo tells the children that Masrur holds the Nidas in her treasure trove – but the only way to gain access to the store is by using a genie trapped in a bottle worn around Masrur’s neck…
Arriving in England during the Civil War, Helen, Terry and Phil find themselves in the cellar of the house belonging to Lord and Lady Courtney, where they meet an old woman called Nan, who mistakes them for the Courtneys’ children. Nan gives the trio candles and then leads them into the safety of the tunnels below the house, away from the approaching conflict between the Roundheads and the Cavaliers; however, after Helen’s candlestick somehow gives her and Terry a mild electrostatic shock, the group inadvertently splits into to parties; while Nan and Phil meet Rothgo’s past self, a travelling player dressed as a Cavalier, Terry and Helen manage to contact Rothgo’s future self, something only possible with close proximity to the Nidas… Meanwhile, Belor, in the guise of the Courtneys’ housekeeper, is furious to find that the Nidas – which was disguised as a candlestick – has now fallen into the hands of her enemies; however, before she can pursue the children Belor is stopped by the arrival of a squad of Roundheads led by Colonel Chadwick. Using her cunning, Belor convinces the Colonel that not only have Helen, Terry and Phil stolen a valuable heirloom, but that they also know the whereabouts of the fleeing king; the Colonel immediately dispatches his men into the caves – and soon Phil and Rothgo are captured by the Roundheads and brought in for questioning…
As Terry, Phil and Helen journey through the labyrinth, Belor intervenes and delays them in a time vortex; she then travels ahead of them, arriving during France’s infamously bloody Revolution. Materialising in a church carved out of a cave, Belor casts a spell on Rothgo’s past self, a French aristocrat, to ensure that he will not recognise the three children when he meets them; then, having disguised herself as a woman named Juliette, Belor uses her feminine wiles to trick Rothgo into believing her to be a friend. Belor introduces Rothgo to her fellow revolutionaries, a motley gang led by the zealous Citizen Pierre; however, Pierre feels jealous over Rothgo’s attentions to Juliette, and promptly accuses Rothgo of being a spy; luckily a demonstration of Rothgo’s magic quickly puts an end to Pierre’s threats. Elsewhere, the children finally arrive, only to find themselves trapped in a tunnel, and their confusion increases when they see witness Rothgo’s past self apparently enjoying a dance with Belor. Back in the church, a group of French soldiers arrive, led by the newly-elected Proconsul Julien. When Belor manages to trick Rothgo into thinking that Julien is her in disguise, Rothgo’s ranting results in his arrest as a traitor – and is immediately sentencing to death…
Pierre’s attempt to blow up the powder kegs using the ‘Nidus clock’ as a timer results in a huge explosion, the force of which blasts the children forward in time to the present. Here they find the labyrinth and Rothgo – who is now close to death. Rothgo frees the children of their obligation to help him, but Helen, Phil and Terry ask for one more attempt to find the Nidas, even though they know that their failure will mean they will be trapped in the past forever. Summoning up his final reserves of energy, Rothgo sends the trio to the original labyrinth, back in ancient Crete. Here the children find the Nidus disguised as a bust of a Minotaur, a fearsome, bull-headed creature, but when Terry attempts to touch the object he discovers that it is protected by a powerful force. They are interrupted by the arrival of Theseus and his companion, Ariadne – none other than Belor in disguise; Theseus wants to slay the Minotaur, but Belor manages to persuade him to take the Nidus instead. Using his sword, Theseus removes the powerful object, causing a cave-in that traps the children. Terry, Phil and Helen are about to give up hope when they meet Rothgo’s past self, Daedelus, the creator of the maze; however, when they try to show Rothgo a vision of his future self as proof of his real identity, they are shocked to see Belor defeat their friend. Unless Phil, Terry and Helen can retrieve the Nidas, it seems that Belor has finally won…
