Many of the character's lives before the crash are explored, and they are detailed here;
Ned Pilgrim is an art teacher and a family man, having maried the woman of his dreams, with whom he has a son. His wife Hallie becomes pregnant again, but loses the child, causing her to go into a state of depression. One night she goes missing, causing Ned to become depressed and he can barely take care of his own son. He decides to take a cruise on the luxurious La Mer so he can try to get his mind straight, leaving his son Austin with his sister, promising to return to them in a week.
Dominic Frost is an alcoholic who begins going down the road to recovery when he meets Beth Moxley, a married woman he eventually falls in love with and they begin an affair. After accidentally murdering her abusive husband, Dominic is forced to abandon Beth and board the cruise to flee the authorities.
Jonathan Harker is a lawyer with a wife and young, sick son. Jonathan gets too caught up in putting away convicted murderer, teenager Charlie Hume, for the accused murder of Summer St. Clair's parents, causing rifts with his family and co-workers. Jonathan soon faces a devastating loss, as his own preoccupation with the Hume case causes his son Lucas not getting his medicine in time, leading to Lucas' tragic death.
Emily Campbell is a young woman leaving her homeland of Scotland to start a new life in Los Angeles, which is where she meets Mike, who she eventually marries. It turns out Mike is only a figment of Emily's imagination, and her estranged father places her in Santa Rosa Mental Institution to help her control her mental condition.
Summer St. Clair is a world traveler who wrote a memoir after experiencing the brutal murder of her parents at the hands of her ex-boyfriend Anatole. After receiving a threat, Summer attempts to pull the book before it goes on sale and lock up an innocent teenager that was framed for her parents' murder, but her publicist and close friend Iris talks her out of it. Summer puts the book on sale and returns to Australia to hide out. While on the La Mer four years later with Iris for a nice catch-up, Anatole interferes. Finally realizing she can't live her life while he's alive, Summer contemplates killing Anatole, but the ship wreck interferes, not letting her become the kind of monster she despises.
Theo Benoit is a gifted businessman who oversaw a merger between two of the world's biggest companies: Paik Industries and Avias Corporations. Under the tutalage of Malcolm Nammock, Theo planned to exploit the merger in order to give his side more power. However, he fell in love with Ji Yeon Paik and soon exposed his company's plans, resulting in the destruction of their relationship.
Roz Mulheronis a young woman from London born into the lower class of the inner city. She looked after her family, including Emus, Veronica, David, and Eden. However, she was closest with her older brother Adrian. After learning of his ties with the crime life she knew too well, Roz killed a member of the crime world in order to get Adrian a chance at a free life while she spent time in bars.
Mats Lindgren is a former prisoner who took the conviction of Annie Rand in order to save her the charges of murder. He was wrongly diagonosised a sociopath due to the mysterious murders, but took his prison time to write a book called Encounter at Far Point.
Plot: A trip to the jungle for food leads to a trial of temptation for Dominic. Meanwhile, Ned and the others have to deal with the fallout of the mysterious man in the jungle. Flashback explores the origin of Dominic's ring.
Plot:Ned brings along Marcus and Summer in an effort to track down Annie. Meanwhile, Emily struggles with her mental condition and Roz deals with heavy amounts of guilt just as her past comes creeping back to haunt her. Flashbacks explore the many relationships in Ned's life and how exactly he wound up on the cruise.
Plot:Theo, Roz, and Emily are captured by a group of natives, who have an agenda for Theo. Meanwhile, Ned prepares for his mission against Leigh's wishes. Flashback explore Theo's life as a business worker.
Plot:Roz is taken to a mysterious Temple in order to be healed from her fatal gunshot, but Emily is unsure its worth the consequences. Meanwhile, Dominic finds something from his past that makes him question his friendship with Annie and Mats, while Harker gets close to findiing a way off the Island.
Plot:Jonathan wrestles with his past, causing tensions between himself and Summer, as Ned, Marcus, and Theo come to agreeance on how to deal with Malcolm Nammock. Flashbacks focus on Jonathan attempting to piece his life back together after the death of his son, Lucas.