四位女高中生躺臥在沙灘上。在修學旅行中被捲入事故的她們漂流到了無人島。四人輪流做了自我介紹，對於現狀顯得非常安定的,不過，非常安定的情況的鬼島譽放言「我不是第一次這樣遭難了。」相當具有衝擊力的言辭。

為了確保水源，她們決定各自去島上探險。明日香發現了是枯萎的河底，她要從潮濕的泥土中取出水？另一方面，留下的紫音和睦在因水分不足而導致的意識朦朧中，許下了某個「約定」。

譽和明日香為了尋找食材而進入森林。明日香發現了和芋頭相似的植物後非常高興，但是譽卻指出了食材可能存在的危險性。譽對於想吃而對其撒嬌的明日香感到吃驚，為了確認是否能吃，譽突然掀開了明日香的裙子！？

某日，發現了松鼠和兔子痕跡的譽等人立刻開始試著佈置圈套。為了生存而利用島上的東西，苦戰的同時真正的陷阱佈置完成！明日香懷著輕鬆的心情試著中了陷阱圈套…

譽等人潛入海裡尋找食物。雖然人類在水中的視野有些模糊，但譽還是巧妙地製作了副水中眼鏡，尋找海螺和牡蠣……在嚴酷的環境下，她們無論是在體力上還是精神上都漸漸被逼入絕境。譽想起了父親以前教她的一句話:「難受和悲傷的時候，就是要燒烤。」

明日香和睦前去查看陷阱的情況，那個陷阱已經捕捉到了兔子，但是已經沒有時間前去尋求譽的幫助了！如果放任不管的話，兔子可能會逃走…為了生存，兩人所做出的選擇是？

為了應對長期的遇難生活，譽等人決定在海島上展開探索，竟然發現了民居！這樣就能獲救了！滿懷希望的4個人向民居跑去，但是在那裡只是一片腐朽的廢墟…看著充滿遺憾的3人，譽從廢墟中找到了生存下去的重要工具！

繼續探索的4人發現遠處升起的煙，急忙跑向海岸的岩石場！難道有人在？但是在那裡的卻是溫泉？！大家一起用溫泉治癒因探索而疲憊的身心吧！

After following the honey bees that have been flying around the camp to their hive, the girls decide to try to get the honey. It isn’t uncommon for people to die from bee stings, so how will they manage to deal with the bees?! Then, Shion boards a raft to try her hand at fishing and gets caught up in…

Shion has been swept away by a rip current and the others are at a loss. That’s when Homare decides to build a new raft and go after her! She breaks her fathers rule of "you own life comes first," risking her life to go save Shion, but in the vast ocean, Homare can’t find her… Having exhausted every option she can think of, suddenly Homare remembers one of her father’s teachings…!

Homare finds the solitary island where Shion washed ashore and the two are reunited. But there’s no time to rejoice. With no food or water, succumbing to dehydration is only a matter of time… All they have is filthy water they find in a cave… In this dire situation, the two of them use a secret technique for rehydration!? Will Homare and Shion make it back to the island?