If ever there’s a perfect genre movie to encapsulate that cabin-fever madness many of us are likely feeling about now, it’s Robert Eggers’ sophomore feature The Lighthouse, currently available to stream on Prime Video. A hallucinatory tale of two lighthouse keepers struggling to maintain a semblance of sanity during their stint on a remote, isolated New England isle makes for one hell of a visual journey rife with dread, farts, and mermaids. It’s also not always the easiest to decode. True to form, Eggers’ submersion into the period and an over meticulousness in research mean The Lighthouse is a richly layered folktale offering new insights with every watch. Hark, Triton! Hark! There be plot spoilers ahead.

Co-written with his brother Max, Robert Eggers’ revealed in an interview that it was a true-life tragedy that inspired the barebones outline of The Lighthouse, one that’s turned into a folktale over the years. That tragedy, known as the Smalls Lighthouse Tragedy or Incident, changed the way British lighthouses were operated. In 1801, keepers Thomas Griffith and Thomas Howell were stationed at the aging lighthouse on a small, rocky island twenty miles west of Wales. It was widely known that the pair didn’t get along in the best of circumstances, often fighting and threatening bodily harm. So, when Griffith died in a freak accident, Howell was too afraid to cast the body out to sea; he assumed everyone would suspect him of murdering Griffith.

Instead, Howell built a coffin for Griffith and tied it to the rocks outside the keeper’s house while he continued his duties of keeping the beacon lit. Over the winter, waves battered the coffin against the rocks, and the corpse along with it, making its arm appear to wave and beckon. The beckoning arm and isolation broke Howell down over time, so when his replacements arrived to relieve him, he was unrecognizable. Henceforth, it was mandated that lighthouse teams be comprised of three men, not two.

In Eggers’ The Lighthouse, that’s the exact setup; Thomas Howard (Robert Pattinson) and Thomas Wake (Willem Dafoe) are stationed on a rocky isle to man the lighthouse for a month, and their drastically different personalities cause them to clash almost constantly.

There’s a bit more to Howard and Wake, though; they represent Greek myths Prometheus and Proteus, respectively. Prometheus was a Titan with a reputation as a trickster. He stole fire from Olympus and gave it to humanity, which enraged Zeus. As punishment, Zeus chained him to a rock. In The Lighthouse, Howard is a trickster in the sense that he hides his true identity for most of the film; he assumes the identity of Ephraim Winslow, a man he killed during his tenure as a lumberjack. The rock that he’s tethered to is both the island and the consistent chores that Wake gives him. He’s drawn to the lighthouse beacon throughout the film, but Wake continuously denies him. That beacon likely represents the forbidden knowledge of Mount Olympus. The knowledge that ultimately proves too much for his mind to bear. The final parting shot of Howard is of seabirds pecking away at his organs, another nod to the myth; Zeus ensured that an eagle would feast on Prometheus’s liver each day as part of his punishment.

As for Wake, he’s the Old Man of the Sea or sea-god Proteus. One of Proteus’s most common places of dwelling were islands. He was prophetic and knew all things past, present, and future. Above all, though, he hated revealing what he knew. This tracks with Wake’s character, depicted as an older, wiser superior to Howard that keeps his real thoughts relegated to a journal. One that Howard finds in the final act, with disastrous results. Proteus was a shapeshifter with dominion over the sea and its creatures. This again tracks with the actions of Wake throughout the narrative. Mostly, Proteus was unpredictable in behavior. It’s this aspect that fuels the contentious relationship between the lighthouse keepers. As far as Wake is concerned, this island is his domain, and everything on and around it belongs to him. His mood is consistently erratic; when Howard confesses to not liking Wake’s cooking, Wake invokes Poseidon and unleashes an eerie sea curse upon Howard. It’s an over-the-top, wrathful response to the insult.

Greek myths and true-life inspired folktales don’t precisely scream horror, though, do they? While it’s clear that Eggers is playing around with genre here, the horror is built into the spiraling insanity of the two men. In the dread as they escalate their violence. Moreover, it’s baked into the Edgar Allan Poe’s “The Tell-Tale Heart” parallels of the Small Lighthouse Tragedy. Eggers revealed that he drew from H.P. Lovecraft’s Weird Tales pulp magazines, too, but less in the sense of Elder Things and more fear of the unknown tinged with the supernatural. The Lighthouse draws from the weirdness of the magazines, and the tension the stories evoked. That Eggers injects plenty of humor into the film further blurs the genre lines.

The way Eggers presents this maddening tale of identity and unraveling sanity amidst a mythical period backdrop leaves much up to the viewer to parse through and decipher. However, you can bet every visual, frame, and seemingly throwaway line of dialogue serves a purpose. Two movies in and the filmmaker has demonstrated an obsessive level of detail in his craft. Whereas The Witch offers a straightforward horror folktale, The Lighthouse presents an almost unquantifiable folktale as unpredictable as the sea itself.

Both exploring vastly different but equally dark corners of New England.