Two teenage passengers of a luxury ship fall overboard, eventually washing up on the same beach of a deserted island. The girl, Claire, wanders along the beach, singing to the sunset. Her singing attracts the boy, who is suffering from amnesia and has no idea who he is, despite Claire's claims that he is her long-lost boyfriend, Sam. Although he doesn't remember her at all, they decide to stick together and find a suitable cave to spend the night in. As they explore the island, they discover new projects to build, new ways to cook the food they find, and slowly reveal each other's memories.
After exploring the jungle-like area of the island and helping Claire overcome her fear of water, the pair build a bridge out of a fallen log and cross over to the other side of the jungle. They soon find themselves in the Quarry where they meet another survivor: a young man named James.
Although James has no problem with Claire, he deeply distrusts Sam, claiming that he witnessed him confront some men who were attacking a lab back on the ship. When Sam came out, the men doubled over in pain as if he had some sort of evil influence over them. The men declared that if they went down, so would the ship. Claire defends Sam, causing James to think maybe he isn't so dangerous if he has been with a clearly-unharmed Claire all this time. Still slightly suspicious, James agrees to join their group and helps to survive and explore the island..
As Sam and James explore a swampy area, they come across an alligator. James attempts to drive it away, but is thrown back, compelling Sam to defend the stunned James from the alligator until the dangerous creature gives up and goes away. Although the experience was frightening, it also forges a friendship between the two boys. When they find a wide river, they work together to build a raft and sail to a new area.
Fighting their way through a cave of bats, they find themselves in a grassy valley containing a large lake and a derelict entrance to an abandoned laboratory complex. Sam has a flashback revealing that he is actually Eric, Sam's twin brother. He and his brother lived with their scientist parents on the island before it was destroyed in a massive earthquake. The group spend the night in a room already furnished with beds, a shelving unit, and a sink able to store water.
Exploring further, the trio discover a field where they witness a plane crash. Rushing to the broken aircraft, they discover a young girl named Kumiko, who appears to have flown the plane herself. Though alive, she is injured, and the group needs to bring her mugwort to heal her. Once revived, she agrees to join their team. Once the memo near her plane is found, Kumiko is asked to tell the others the island's secrets. Over a period of three days, she explains that the scientists at the facility, including her father, were trying to develop a "miracle drug" that would be able to enhance the human race's abilities to survive in any environment. When they find her father's diary, however, it reveals that while the drug did enhance the human subjects' abilities, it also spawned a virus that would over a period of time greatly harm anyone who came near the subject.
Using the passcode written in the diary, they unlock the submarine room and reveal its hidden occupant: Sam. Overjoyed and shocked to find her long-lost boyfriend alive, Claire tries to open the door where he's shut himself away but he stops her. He explains that he was indeed a test subject of the drug the facility was developing and consequently is infected with the virus. He asks her and the others to finish the cure that his mother was working on.
After assembling all the ingredients and giving the completed medicine to Sam, everyone finally escapes the island on the submarine.
Claire: A young singer who was hired to provide musical entertainment on a luxury cruise liner. She is thrown overboard when the ship suddenly rocks.
Eric: A young man who was a passenger on the same cruise liner Claire performs on. He is also thrown overboard when the ship rocks. The shock of the accident causes him to temporarily lose his memory, even his own name.
James: A fifteen-year old boy skilled in martial arts who survived the ship's sinking. He is deeply distrustful of Sam/Eric at first.
Sam: Eric's twin brother and Claire's long-lost boyfriend.
|Storyline||Eric, Claire||Vaccine||Secret Base||None|
|Radio||All||Portable Radio||Plane Crash Cliff, then First Beach||None|
|Boat||Eric||Live for 6 weeks||Secret Base||None|
|Plane||Kumiko||Repair Plane , Vaccine||Plane Crash Field||Lighting|
|HAM Radio||James||Turn on Power||Cherry Blossom Field||Heights|
|Raft||Eric, James||Build Raft, Sea Map||Last Beach pass Gas Area||None|
|365 Days||All||Live for a Year||Anywhere||None|