In a bold expansion of the Whoniverse, the BBC has dropped a chilling five-part miniseries that feels like a wake-up call from the depths. The War Between the Land and the Sea, created by Russell T Davies, premiered with a double bill on December 7, 2025, on BBC One and iPlayer, plunging viewers into a world where sirens blare over flooded streets, coastal cities teeter on collapse, and an ancient aquatic species claws its way back to reclaim the planet. Without the Doctor’s familiar blue box to save the day, this spin-off thrusts ordinary humans – and the beleaguered forces of UNIT – into a desperate standoff against extinction. Russell Tovey stands at the forefront as an unlikely hero, his performance brimming with raw fear, fiery determination, and quiet defiance, while Gugu Mbatha-Raw’s enigmatic presence adds layers of eerie calm and buried secrets that amplify the global panic.

The series wastes no time immersing audiences in dread. It opens with haunting images of stormy seas and submerged ruins, as humanity’s long abuse of the oceans – pollution, overfishing, plastic waste – awakens the Homo Aqua, a fearsome ancient race once known in Whoniverse lore as the Sea Devils. These reptilian humanoids, evolved parallel to land-dwellers millions of years ago, emerge dramatically, revealing themselves in a shocking incident that spirals into international crisis. Cities drown under weaponized tsunamis, debris from humanity’s waste rains back in apocalyptic storms, and negotiations teeter on the edge of all-out war. The Homo Aqua demand restitution: withdraw from the seas or face annihilation. With the entire population at risk, UNIT – the Unified Intelligence Taskforce – mobilizes, but without extraterrestrial intervention, the stakes feel unbearably human.

At the center is Barclay Pierre-Dupont, played by Russell Tovey with heartbreaking vulnerability. Barclay is no seasoned operative; he’s a low-level UNIT staffer whose daily grind involves arranging transport for higher-ups. An administrative glitch catapults him into the role of humanity’s ambassador, chosen inexplicably by the Homo Aqua for his unassuming honesty. Tovey anchors the chaos brilliantly, transforming Barclay from a nervous everyman – twitching with impostor syndrome and family worries – into a figure of quiet heroism. His wide-eyed terror in early confrontations gives way to defiant resolve, as he navigates diplomatic minefields and personal sacrifices. Tovey’s performance is full of fire: moments of trembling fear during underwater descents, flashes of anger at bureaucratic betrayal, and tender defiance when protecting loved ones. It’s a role that demands emotional range, and he delivers, making Barclay the relatable heartbeat amid escalating horror.

Opposite him, Gugu Mbatha-Raw embodies Salt, the Homo Aqua’s enigmatic delegate. Emerging from a massive tank on the Thames in a spectacle of power and poise, Salt speaks flawless English with an otherworldly calm that only heightens the unease. Mbatha-Raw, layered in intricate prosthetics that blend reptilian features with graceful fins, conveys volumes through subtle gestures – a tilt of the head hinting at ancient wisdom, a flicker in her eyes suggesting deeper motives. Her eerie serenity masks potential fury, burying secrets from the ocean’s abyss that unravel across episodes. Is Salt a voice of reason or a harbinger of doom? Mbatha-Raw’s restrained intensity deepens the panic, turning negotiations into psychological battles where every word feels loaded.

Supporting the leads, Jemma Redgrave reprises Kate Lethbridge-Stewart with commanding authority, leading UNIT through isolation and conspiracy as political forces undermine her. Alexander Devrient returns as Colonel Ibrahim, providing steadfast military grit, while Ruth Madeley as Shirley Anne Bingham adds sharp intellect and heart. The ensemble grounds the spectacle, exploring fractured alliances as Downing Street schemers, corporate interests, and military hawks push for aggression over diplomacy.

Davies, drawing from environmental anxieties and classic Whoniverse foes, crafts a slow-burn thriller that builds inexorably. The five episodes – tightly paced at around 45 minutes each – layer dread scene by scene. Early installments establish the crisis with practical effects that immerse: vast underwater habitats, plastic-fueled cataclysms hurling debris skyward, and tense beach standoffs. As Barclay descends into Homo Aqua realms, the visuals turn epic – bioluminescent cities, swirling currents hiding ancient forces. Davies weaves socio-political commentary seamlessly: humanity’s environmental hubris triggers the awakening, with Homo Aqua weaponizing our waste in visceral retribution. Yet it’s never preachy; the terror feels earned, ordinary moments – a family dinner interrupted by alerts, a quiet negotiation turning deadly – pulsing with danger.

Critics have hailed it as the BBC’s most terrifying drama in years, a mature evolution pushing boundaries with tougher tones absent the Doctor’s whimsy. The absence of that safety net heightens stakes: characters pushed to limits, moral compromises raw and unforgiving. Episodes escalate masterfully – a “Plastic Apocalypse” in episode two overwhelms with scale, while later installments delve into betrayal, underwater alliances, and war-torn London chases. Cliffhangers hit hard, blending emotional gut-punches with shocking revelations, leaving viewers sleepless.

Fans are already obsessed, bingeing the available episodes and theorizing wildly about the finale. No one feels prepared for the culmination: escalating threats from radical Homo Aqua factions, Barclay and Salt’s evolving bond hinting at forbidden understanding, and UNIT’s desperate gambits. Will diplomacy prevail, or will ancient forces drown the land? The series refuses easy answers, lingering in ambiguity where humanity’s flaws mirror the invaders’ wrath.

In a landscape of flashy spectacles, The War Between the Land and the Sea stands out for its restraint and depth. Practical sets and effects ground the fantastical, while performances – Tovey’s defiant everyman, Mbatha-Raw’s inscrutable ambassador – elevate the terror. It’s a monster unleashed quietly, seeping into nightmares with rising waters and awakening horrors. As cities fracture and secrets surface, this is BBC drama at its most primal: a warning from the deep that humanity ignores at its peril. Dive in if you dare – but be warned, the finale will leave you gasping.