Josh Hartnett Battles A Mysterious Sea Creature In Netflix’s New Six-Part Thriller ‘Below’ — But The Trailer Refuses To Show What’s Lurking Underwater

Something dangerous is moving beneath the ocean off Newfoundland — and Netflix is deliberately refusing to show viewers exactly what it is.

Josh Hartnett leads the new six-part limited series Below, playing a fisherman whose isolated coastal community begins experiencing a series of increasingly disturbing and violent events connected to a mysterious creature lurking beneath the water.

The official trailer establishes the threat without giving audiences a clear look at the monster itself, putting the emphasis instead on fear, uncertainty and the reactions of people who suddenly realize the ocean surrounding their home may be hiding something terrifying.

For Hartnett’s Calvin Penney, however, the mystery quickly becomes far more than a problem threatening the local fishing community.

His own family becomes caught in the nightmare.

Something Is Lurking Off The Newfoundland Coast

Calvin is a fisherman living in a small Newfoundland community where the sea is inseparable from everyday life.

That relationship changes when strange incidents begin occurring around the water.

Something appears to be moving beneath the surface, but the people living nearby have little understanding of what they are confronting.

Rather than immediately revealing its creature, Below appears determined to make that uncertainty part of the horror.

The trailer offers signs of its presence and the destruction surrounding it while withholding the complete picture.

For Calvin and his neighbors, the danger is particularly unsettling because retreating from the ocean is hardly a simple option. Their livelihoods and way of life are deeply connected to the waters that have suddenly become threatening.

Netflix describes Calvin’s struggle as a fight not only for his family and community, but also for their disappearing way of life.

Calvin’s Son Develops Frightening Symptoms

The situation becomes much more personal when Calvin’s son, Wade, begins experiencing disturbing symptoms.

Wade is played by Stranger Things star Charlie Heaton, and his condition appears to deepen the mystery surrounding whatever is happening offshore.

Calvin cannot simply wait for the danger to disappear.

Searching for answers brings him together with Fonda Howander, a marine biologist played by Mackenzie Davis.

The pair begin investigating the mysterious creature and the secrets connected to the waters surrounding the community.

That gives Below two intertwined mysteries: what is actually living beneath the surface, and what connection does it have to the increasingly frightening events occurring on land?

The series has six episodes to unravel those questions.

Josh Hartnett Leads The Cast

Hartnett takes center stage as Calvin, continuing his recent run of high-profile film and television roles with a character far removed from a conventional action hero.

Calvin is an ordinary fisherman suddenly placed in extraordinary circumstances, forced to protect the people around him while confronting something he barely understands.

Charlie Heaton plays his son Wade, while Mackenzie Davis joins the story as marine researcher Fonda Howander.

The ensemble also includes Rohan Campbell, Ruby Stokes, Kaleb Horn and Willow Kean, with Natasha Henstridge and Mary Walsh also listed among the cast.

Together, the characters populate the isolated community at the center of the mystery, where an unexplained threat from the ocean begins disrupting lives already shaped by the challenges of a changing way of life.

‘Below’ Takes Inspiration From Spielberg And Carpenter

The series was created by Jesse McKeown, whose previous credits include The Umbrella Academy and 19-2.

McKeown has cited Steven Spielberg and John Carpenter as influences on the project, particularly the handcrafted genre filmmaking associated with their older work.

Those influences make sense given the premise.

Below has the ingredients of a classic creature thriller: an isolated location, ordinary people facing an extraordinary threat, a monster that remains largely unseen and a growing realization that something familiar has suddenly become dangerous.

Newfoundland itself also played an important role in shaping the series.

Its rugged landscape, remote coastal communities and local legends provided inspiration for the world surrounding Calvin and his family.

Rather than treating the setting as little more than scenery, the series places the community’s relationship with the ocean at the center of its story.

Netflix Is Keeping Its Monster A Secret

Perhaps the most intriguing choice in the trailer is everything Netflix does not show.

A creature feature could easily sell itself by putting its monster front and center.

Below takes the opposite approach.

There are indications that something significant is moving through the water. The consequences of its presence become increasingly difficult to ignore. Characters clearly understand that they are dealing with something far beyond an ordinary maritime threat.

But viewers are denied a clean reveal.

That makes the unknown itself part of the suspense.

How large is it?

Where did it come from?

What does it have to do with Wade’s frightening symptoms?

And why are these events happening now?

The trailer leaves those answers for the series itself.

The Newfoundland Setting Makes Escape More Complicated

The location also gives Below a different atmosphere from a conventional monster story.

Calvin and his neighbors live in a place where the sea is not simply something outside their windows.

It represents work, history, identity and survival.

The threat beneath it therefore attacks something much larger than individual characters.

Calvin is trying to keep his family alive, but he is also attempting to protect a community and a way of life already facing an uncertain future.

That tension adds another layer to the creature mystery.

Even without the monster, the community is changing.

With something dangerous now moving through its waters, that fragile existence becomes even harder to preserve.

Six Episodes To Discover What Is ‘Below’

Keeping the story to six episodes gives the series a relatively compact framework for its mystery.

Rather than stretching the creature’s identity across a lengthy season, the limited-series format can concentrate on Calvin’s investigation, Wade’s condition and the escalating danger around the community.

The setup also puts Hartnett at the center of a very different kind of survival story.

There is no obvious enemy Calvin can understand from the beginning.

He is facing something hidden in an environment he has spent his life believing he knows.

And if the trailer’s refusal to reveal the creature is any indication, audiences may spend much of the story knowing little more than he does.

A New Old-School Creature Thriller For Netflix

The combination of Hartnett, an isolated Newfoundland fishing community and an unseen ocean threat gives Below the feel of an old-fashioned creature feature filtered through a modern limited-series mystery.

Its Spielberg and Carpenter influences are particularly intriguing because the series appears interested in suspense before spectacle.

The monster exists.

Its effects are becoming impossible to ignore.

But seeing it clearly is apparently another matter entirely.

That restraint leaves Below with one powerful mystery heading into its premiere: Netflix has told viewers that something terrifying is beneath the water without showing them exactly what they should be afraid of.

They will have six episodes to find out.

Below premieres exclusively on Netflix on October 8, 2026.