Wide Sargasso Sea — based on the 1966 novel by Jean Rhys, originally aired by the BBC in 2006 and finally releasing to U.S. audiences on DVD later this month — is a sensuous look at a descent into madness. Ostensibly presented as a prequel to Charlotte Bronte’s Jane Eyre, the story is about Mr. Rochester’s first wife, Antoinette Cosway, and how she transformed into that ghostly lunatic locked in the tower at Thornfield Manor.

Edward Rochester, a disenfranchised second son, has come to Jamaica to seek his fortune at his father’s behest. Edward could not be more English: tight-lipped, excruciatingly proper, and respectably swaddled in good English woolens. He is entirely unprepared for life in the Caribbean – the warm, sticky, scented air, the beautiful women, the copious amounts of rum – and is unable to do much more than protest feebly when his friend Richard fixes him up with Richard’s stepsister, Antoinette Cosway.

Antoinette is lovely, innocent, and presumably quite unlike any English ladies Edward has ever met, barefoot and dreamy. She introduces him to the beauty and wonders of her island home and he is quickly smitten with her. Before long they are married, over the odd protestations of Antoinette’s Aunt Cora and amid the murmured whisperings of the Jamaican townsfolk. Dizzily in love, the newlyweds head to the Cosway summer home in the mountains for their honeymoon.

The mountain house is beautiful and decayed, which seems to be the state of nearly everything in Jamaica, as Edward soon discovers. The couple spends their days exploring their surroundings and each other’s bodies; Antoinette is the happiest she has ever been and Edward relaxes for the first time in his life.

It doesn’t take long for things to fall apart, of course. Antoinette’s nurse, Christophine, is openly hostile towards her former charge’s new husband; the other servants are dodgy and impertinent. Edward begins to hear rumors that his wife’s mother was insane and tried to kill her own husband. Digging deeper, he uncovers additional secrets, including that madness likely runs in the Cosway family. He retreats into his Englishness – well on his way to becoming the harsh, withdrawn Rochester we know from Jane Eyre - and Antoinette’s fragile psyche starts to disintegrate. By the movie’s end, it is uncertain whether her insanity is wholly genetic or in large part due to her husband’s treatment of her.