For once, a film claiming to be “based on a true story” actually is. And in more than just a passing way. THE LIGHTHOUSE is based on the Smalls Island Incident of 1801. Which, as noted in the film’s epilogue, changed how British lighthouses were crewed until they became automated in 1980. It also stays quite close to the actual events, or as close as possible given the events and their aftermath.

THE LIGHTHOUSE starts out with intercut scenes of a bare-knuckles boxing match and a man praying. But the film quickly takes a different direction. Two very different men Thomas Howell (Michael Jibson) and Thomas Griffiths (Mark Lewis Jones THE PASSING) are sent to run the lighthouse. Howell is a devout Christian with a dark past. Griffiths is a much more worldly individual and they clash almost immediately.

A monstrous storm roars in and cuts them off from the mainland. And any hope of rescue or resupply before their supplies run out. As desperation rises and rations dwindle, secrets are revealed and madness looms in the shadows.

THE LIGHTHOUSE is billed as a thriller. It received plenty of attention from UK genre sites on its release there last year. But I can’t really call it either horror or a thriller. It’s much more of a dark psychological drama that occasionally pushes the boundaries of the genre. Much like another British piece I recently reviewed, DARK DITTIES PRESENTS MRS. WILTSHIRE, it uses limited sets and a very small cast to create a tense, claustrophobic environment to explore the darker realms of the mind. They’re human dramas first, any genre elements are careful additions.

Director Chris Crow (PANIC BUTTON, DEVIL’S BRIDGE) and co-writer Paul Bryant have taken a somewhat obscure slice of history and milked it for everything they could while staying true to the facts. They are greatly aided in this by excellent performances from both of the leads. This is essentially a two-character story. Thankfully what could have been tedious and annoying, especially the bickering about religion, becomes quite compelling in their talented hands.

For those willing to do without traditional horror trappings, THE LIGHTHOUSE will be an excellent choice with its sense of dread and impending doom.

Nominated for five BAFTA awards including Best Director and Best Actor, winning Best Visual Effects, THE LIGHTHOUSE opens in select theaters July 6 and VOD July 10 from Uncork’d Entertainment.