Volcano

The episode opens on Kembel, where the Daleks prepare to test their formidable Time Destructor, a weapon designed to manipulate temporal reality. Witnessing this pivotal moment are Chen and Celation, whose earlier contributions to the Dalek cause are acknowledged. The Daleks select Trantis, a seemingly expendable figure, as the unwilling test subject for the weapon's inaugural activation. However, the test proves disastrously unsuccessful; the Time Destructor fails to function, revealing a critical flaw in its taranium core. The Daleks quickly deduce that the taranium Chen provided was counterfeit, a result of the Doctor's earlier intervention and a clever swap. Enraged by this deception and the weapon's failure, the Dalek Supreme condemns Chen for his treachery, ordering him to await a time machine that will transport him to Skaro for severe punishment. Simultaneously, the Daleks ruthlessly exterminate Trantis, who, having served his purpose as a test subject, is now deemed obsolete. Meanwhile, aboard the TARDIS, the Doctor, Sara, and Steven detect that they are being relentlessly pursued. Sara, ever pragmatic, advocates for an immediate return to Kembel to neutralize the Dalek invasion fleet, but the Doctor, prioritizing evasion, steers the TARDIS away. In a desperate attempt to shake off their unseen pursuers, the Doctor makes an impromptu landing at a cricket match in 1966 London, causing a brief, comical disruption before dematerializing. Despite this clever maneuver, the Daleks remain hot on their trail, confirming the Doctor's failure to escape. Back on Kembel, the Daleks, with renewed determination, prepare a specialized time machine, compelling a now terrified Chen to accompany a task force dispatched to hunt down the Doctor and recover the authentic taranium. This act establishes the core conflict of the Daleks' relentless pursuit and the Doctor's initial, failed attempts at evasion.

The TARDIS materializes on Tigus, a desolate volcanic planet characterized by steaming rivers of lava and an inhospitable landscape, a stark contrast to their previous brief stop on Earth. The Doctor, recognizing the immediate danger of their location, plans a swift departure, but their escape is thwarted. Steven observes that their pursuers have also landed, confirming the Doctor's earlier suspicions. Unbeknownst to them, the source of this new threat is the Monk, who emerges from a camouflaged rock formation, binoculars in hand, eagerly spotting the TARDIS. The Monk, driven by a desire for revenge stemming from his previous defeat by the Doctor, meticulously circles around the unsuspecting time travelers. He reaches the TARDIS and, with a small pencil laser, sabotages its lock mechanism, rendering it inaccessible. As the Doctor and his companions continue their search for their pursuer, the Monk reveals himself, brandishing a large rock in a comically aggressive stance. A tense, yet surprisingly cordial, exchange ensues, during which the Monk gloats about his successful act of sabotage, reminding the Doctor of his own past predicament in 1066. He revels in leaving the Doctor marooned on Tigus, believing his revenge complete. The Doctor, however, maintains his composure, immediately turning his attention to the damaged TARDIS. Upon discovering the sabotaged lock, the Doctor, demonstrating his characteristic ingenuity, removes a unique ring from his finger. He uses the ring to reflect the unusual properties of Tigus's sun onto the lock, effectively reversing the Monk's interference. With the TARDIS repaired and operational, the Doctor, Sara, and Steven dematerialize, leaving a frustrated and disbelieving Monk behind, who furiously vows to continue his pursuit. The Doctor anticipates the Monk's renewed chase, instructing Steven to monitor for his TARDIS's signature. This act intensifies the chase narrative by introducing a personal antagonist and showcasing the Doctor's resourcefulness in overcoming immediate threats.

Following their narrow escape from the Monk on Tigus, the Doctor, Sara, and Steven find themselves once again in flight, aware that both the Daleks and the Monk remain hot on their trail. Back on Kembel, the Daleks finalize preparations for their time machine, loading a squad of Daleks and the disgraced Mavic Chen aboard. The Black Dalek issues a chilling ultimatum to Chen: succeed in retrieving the taranium or face annihilation, just like the time travelers. The Dalek task force then uses its space-time scope to pinpoint the TARDIS's current location, identifying it as Earth, London, in the year 1966. Simultaneously, the TARDIS materializes in the bustling heart of Trafalgar Square, moments before midnight on New Year's Eve, 1966. The Doctor, Sara, and Steven emerge into a scene of boisterous revelry, surrounded by cheering crowds and the pealing of church bells, a stark contrast to the desolate volcanic planet they just left. Steven immediately notes the impossibility of carrying out any TARDIS repairs amidst such a vibrant celebration. The Doctor, recognizing the familiar setting, recalls a similar celebratory atmosphere from the Relief of Mafeking, though he doesn't immediately grasp the specific occasion. As the Dalek time machine counts down its final seconds before departure, the episode concludes with the Daleks having successfully tracked the Doctor to Earth, setting the stage for an imminent confrontation amidst the joyous chaos of 1966 London. The time travelers, absorbed in their surroundings, remain unaware of the precise and immediate danger closing in, leaving the audience on a tense cliffhanger as the Daleks prepare to land and engage.