Earth, the future. The genius Sylvest twins, child prodigies, are kidnapped by the mysterious Professor Edgeworth and taken to the planet Jaconda. But who is Edgeworth? Why does he serve the giant slug Mestor? And what is Mestor's plan?

The Doctor takes Peri to Titan 3, a desolate hunk of rock in space where he hopes to find some solitude for a while. Instead he finds the lone but unconscious survivor of a recent spaceship crash in sight of a mound-shaped complex where no formalised structure should exist.

The Doctor arrives on Jaconda, once lush and green, to find it completely devastated by giant gastropods. Old legends about the planet's half-human/half-slugs weren't just myths after all. With or without help from the Doctor and his unpredictable mood swings, Lt. Lang is up for rescuing the twins, who are finally informed of the grand purpose they've been brought to Jaconda to accomplish.

The Doctor and Edgeworth deduce that the real plan of Mestor, the gastropod ruler of Jaconda, will not only destroy Jaconda but lead to the devastation of other planets. Together they hope to thwart him despite his formidable ability at slipping into people's minds and controlling them.

All those on Ravolox are in exponentially greater peril than anyone can comprehend. If anything in the entire universe is to survive, it may come down to the Doctor arguing against machine logic over the value of life.

The scientist Crozier keeps making empty promises and Yrcanos and Peri are seemingly betrayed by the addled Doctor who is sure the Matrix is being manipulated...

While the Doctor helps Dr. Crozier transfer Lord Kiv's brain into a new host skull, Peri accompanies King Yrcanos as he searches for the Alpha Resistance fighters whom he feels, most certainly, will follow him into glorious battle against the Mentors and the Doctor.

As the Possidor Ambassador visits, Sil is appalled to realise Crozier has selected Peri to be the Kiv's new host body - a move Yrcanos takes exception to with devastating results.

With the prosecution case concluded, at last the Doctor is able to present his evidence. It takes place in the future with a new companion and new problems.

As the Hyperion III continues its journey, more mysterious deaths occur.

A course change that takes the Hyperion III closer to a black hole could prove unwise when there are so many aboard ship with hidden agendas. Disappearances continue, a murderer remains at large, and one person finally crumbles under the strain of harbouring a guilty secret.

Zoe and Cully are captured by the Dominators and put to work alongside the survey team while the Doctor and Jamie decide to return to the island to help.

The Doctor and Zoe are interrogated by Rago, who is planning to present his terms to the Dulcian council, while Jamie and Cully try to find a way to strike back against the Quarks.

Jamie and Cully manage to rescue the Doctor's party and together they try to find a way to stop the Dominators before they destroy the entire planet.

The Doctor enters the labyrinth to try and protect Jo from the minotaur but the Master has seized control of Atlantis and prepares to summon Kronos again.

The Doctor is taken "out of time" by the Time Lords and made to face an inquiry into his meddling in the affairs of others, overseen by the Inquisitor. The prosecutor, the Valeyard, soon has the proceedings upgraded to a trial for the Doctor's life. Evidence takes the form of recordings of the Doctor's recent adventures, beginning with his visit to the mysterious world of Ravalox and an encounter with Andromedan space pirates...

The Doctor has an appointment with the Immortal, while Peri finds herself caught up with Glitz and the Tribe of the Free. Meanwhile, Merdeen begins to question all he believes.

The Doctor escapes to rejoin Peri on the surface but shortly becomes the prisoner of a surface-dwelling tribe called The Free. Ravalox isn't Ravalox after all, but before the Doctor can learn much more an irresistible agent from UK Habitat comes to fetch him back.

The Doctor's trial continues. The Valeyard's next piece of evidence for the prosecution concerns the Doctor's recent trip to Thoros Beta. Though originally investigating arms dealing, the Doctor and Peri become embroiled in their old enemy Sil's alarming neurological experiments...

With factions vying for control of the ship, the Vervoids are found to be responsible for the many disappearances. Only the Doctor sees the fundamental but missed point as to why they can't be reasoned with or why they can't be allowed to arrive on Earth.

The final part of this epic adventure. The Doctor and the Valeyard have entered the world of the Matrix. Can the Doctor defeat the evil incarnation of himself ?

The Marshal's premature use of Jaeger's experiment is threatening to destroy Solos' atmosphere and the Doctor returns to Skybase to try and correct the damage.

In 1215 at the castle of Ranulf Fitzwilliam, son Hugh is jousting on a matter of honor against Sir Gillis Estram, the champion of King John, when the TARDIS appears. The Doctor, Turlough and Tegan are immediately hailed as demons and welcomed warmly by the King. Something is wrong with this picture, observes the Doctor.

Earth's ocean floor, 2084. With two superpowers poised on the brink of a devastating photonic war, a missile base comes under attack from the reptilian Sea Devils and Silurians, intent on eradicating the upstart human race and reclaiming the planet…

Lanzarote, 1985. Archaeologist Howard Foster raises a strange metal artefact from the sea floor. But how is it linked to the signal the TARDIS received? Why is Turlough suddenly so worried? And why is Kamelion acting so erratically?