Josh Hartnett plays a Newfoundland fisherman in Netflix's six-part Below

Josh Hartnett plays a Newfoundland fisherman facing an unidentified sea creature in Below, a six-part Netflix miniseries built as a single closed story.

Hartnett stars as Calvin Penney, a fisherman living in a small Newfoundland town. The synopsis has Calvin haunted by his father's mysterious death from decades ago, then forced to fight to hold his community together when something in the water terrorises his hometown. Hartnett is also an executive producer on the series.

The series was created and run by Jesse McKeown, with Jessica Rhoades as executive producer through her company Pacesetter, according to The Hollywood Reporter. Rhoades told the outlet the show is about 70 percent science fact. McKeown put the figure at 90 percent.

It was shot entirely on location. McKeown has a personal link to the setting. He is married to actress Marthe Bernard, who is a Newfoundlander. Hartnett prepared by listening to local radio, including Newfoundland programmes The Fisheries Broadcast and Open Line.

The wider cast includes Mackenzie Davis and Charlie Heaton, according to Netflix. Rhoades previously worked with Hartnett on the Black Mirror episode “Beyond the Sea”. The team held a local screening following its Toronto International Film Festival premiere.

Hartnett has said he was actively not looking for television roles before Below came along, in an interview reported by The Hollywood Reporter. He had seen Widow’s Bay and liked it, but described Below as having a totally different tone.

That distinction matters for viewers scrolling past two sea-set shows. Widow’s Bay is a comedy series on Apple TV, created by Katie Dippold, with Matthew Rhys starring as Tom Loftis, the mayor of an island off the coast of Massachusetts, according to Deadline.

For viewers, this means one cold-water mystery with a small-town anchor, not a crossover or a shared universe. Six episodes. One fisherman. Something below.