On one deceptively calm night, the family dog Stella Artois appears on deck, and given that she had previously fallen overboard in the Indian Ocean, Michael tries to retrieve her.

Questions as to how he came to be on the island are soon replaced by how they are to survive, and despite a thorough search of their new home, Michael and Stella are unable to find any food or fresh water.

After failing to locate their mysterious benefactor, Michael decides to build a fire, in order to stay warm, keep mosquitoes away and potentially signal his whereabouts to passing ships.

After witnessing a ship pass by the island and trying in vain to shout to it, Michael defiantly decides that he will re-build his fire beacon, but in secret, behind some rocks on “Watch Hill”, a big mountain on his end.

Before it can catch on fire however, Kensuke appears, eyes full of hurt and rage, destroys it, and smashes the piece of fireglass Michael used to create the bonfire.

Enraged, Michael charges into the sea, determined to let Kensuke know that he won't be bossed around, but is almost killed after being attacked by a jellyfish.

As their friendship grows, Kensuke confides more and more in Michael, eventually telling him his life story: how he had a wife and son back home in Nagasaki, Japan, how he trained as a doctor, how he joined the Japanese navy as a medic in the Second World War and how his battleship was bombed, which led it to wreck on the island.

Kensuke was also made aware by listening to American propaganda and soldiers that an atomic bomb had been dropped on Nagasaki, killing the entire populace.

He writes a message in a Coke-bottle he had found earlier that day and tosses it out to sea, but it washes up on the beach and Kensuke discovers what he has done.

Michael tries to encourage Kensuke to leave as well, pointing out that he doesn't know for sure if his wife (Kimi) and son (Michiya) were killed and telling him of what a modern and developed nation Japan has become.