Across The Sea was the 15th episode of the 6th Season. Everything was going great. The show was ending well. They were sooooo close to having the best TV show in the history of TV. But Darlton decided to totally screw things up, by revisiting a past mystery. Shame on you, Darlton, shame on you.
One upon a time, the ocean spat up a pregnant woman. She got on land and met Mother. Mother tricked her into coming and living on the Island. The pregnant woman gave birth to Jacob, but then gave birth to The Man in Black. Mother got mad because when she was a little girl she always dreamed of raising a son on a deserted Island. Two sons, however, ruined that dream. So mother got a big rock and smashed the pregnant woman's head in like a mango.
Little Jacob and Boy in Black reminded us that child actors can't act.
Mother showed Jacob the magic light as the source of the Island's happiness, which was probably the worst explaination for anything. Ever.
Boy in Black grew a pair and left home, whilst Jacob become a uber mommy's boy. So Jacob and Mother lived together for a really awkward period of time until Jacob grew up. They did things like knitted together, wore matching clothes, sung songs, and drank wine. This confirms the long-held fan theory that Jacob is, indeed, a virgin.
Jacob got really freaked out when he had an erection while looking at his mom. He decided that maybe he too should leave home.
So, a sexually confused Jacob visited MiB, who had gone off and become popular with the all-men colony on the other side of the Island. They did manly things like hunt boar, built tents, and experimented on time-space. Jacob asked MiB a whole bunch of questions about sex, but MiB was more interested in leaving the Island to find him some real tuss. A smoke monster has got needs and a all-male camp is only slightly satisfying.
Jacob, like the momma's boy he is, ran back home to tattle-tell on MiB. Mother decided to go talk to her other son and convince him to stay on the Island and come home. MiB refused, so Mother - now really old and feeble - managed to knock him out, murder his friends, bury the frozen donkey wheel (which in the future was intact - wha?), and set fire to the Island.
MiB woke up and, realizing his chance to get laid by a woman had been thrawted by his psycho-mom, decided to go kill her. Jacob was sad so he took MiB to the magic light and threw him inside.
Naturally, MiB became a giant column of smoke.
Fan reaction was pretty divided mostly due to the fact that a magic light was introduced as the source of everything. Time-travel, polar bears, a smoke monster, a frozen donkey wheel, a secret society of scientists, wormholes, Eloise Hawking, a flash-sideways presenting an alternative reality, a love quadriangle, evil numbers, evil wine, secret hatches, ghosts, and immortality were all acceptable. But magic light? No sir. We got the draw the line somewhere.
Meanwhile, Freud - an avid viewer of the show - applauded Darlton's willingness to discuss their Opedipus Complex on national television.