Let's Lagoon

As the ferry of his school's field trip collides with something underwater in a dense fog, Yamada is thrown overboard and loses consciousness. Some time later, he awakes to find himself on a kilometer-wide uninhabited island. As days pass without sign of rescue, Yamada takes matters into his own hands and sets about creating a boat as his rations steadily decrease... when he unexpectedly finds a girl from his class, Imaise Chika, swiping some. For the next few days they cooperate in their efforts to survive and escape, until something very unexpected happens.

Later, they are joined by Shibata, an apathetic teacher at their school; Nori Kamiyama,a classmate highly infatuated with Yamada; and Imaise Miki, Chika's older sister and Nori's senpai in the school's Track & Field Club.

Written and drawn by Okazaki Takeshi, Let's Lagoon at first glance appears to be an arbitrarily set up island survival/drama {manga}. A few chapters, however, things take a highly interesting turn.


 * A-Cup Angst: In Chapter 17, Nori manifests envy for Chika's more gifted figure.
 * Accidental Pervert: When Yamada and Chika meet.
 * Blind Without'Em: In chapter 23, Chika can't recognize Nori without her glasses.
 * Clarke's Third Law: Chapter 43, future Yamada shows Chika a plate which shows that the island, called Lagoon, is apparently a manmade resort of four hundred years into the future.
 * Crash Into Hello: Well, technically, the collision happened shortly after they met.
 * Eldritch Location: The island, which throws people back and forward in time with its mist and as Yamada later discovers by chapter 30, it's place where the can set and raise from the same direction. It is subverted by Chapter 43, where it's instead implied to be a malfunctioning manmade resort which time traveled far into the past.
 * Erotic Dream: Very implied to be what Nori was having in Chapter 39, sinc she wakes up and complains about having all of her clothes on while speaking in a seductive tone towards Yamada.
 * Everything's Even Worse with Sharks: Chapter 41 features a shark swimming along Yamada while he is fishing. Nori ends up beating him up with a stick.
 * Green-Eyed Monster: Yamada admits in Chapter 21 he felt envy of Shibata.
 * Hot Springs Episode: Chapter 30 features Chika and Miki taking a bath on a hot spring they discover to exist on the island.
 * Imagine Spot: In Chapter 17, Nori has one of her and Yamada dating.
 * Indirect Kiss: In Chapter 17, Nori is clearly pleasuring herself on the act of drinking from the same cup as Yamada. Miki deduces what is happens and tries to her to act more mature to no avail.
 * In Medias Res
 * Love Confession: Nori confesses she loves Yamada in Chapter 18. He rejects her in Chapter 19, saying for her to give him more time.
 * Love Epiphany: Chika has one in Chapter 46 after Nori tells her knowing instinctively that Future and Present Yamada were the same without being told to means you must love him(that is something she also could do).
 * Ms. Fanservice: Chika, who spends the major part of her screentime without a bra, who she used to make a bandage.
 * No Antagonist: There's no human-like, intelligent antagonist. The one obstacle is the island itself and the time travel phenomenon around it.
 * One of the Kids: In chapter 21, Miki says Shibata is actually much more closer to this than what Yamada thinks.
 * School Swimsuit: In chapter 49, Yamada reveals he has brought a swimsuit to the island when both girls offers themselves to fish. Of his little sister, who is more than ten centimeters lower than either Chika or Nori. Nori tries to wear it since her lack of assets makes her less likely to expose herself while wearing it than Chika. It still don't fits.
 * Set Right What Once Was Wrong:
 * Nori develops that desire from chapter 16 onwards so she can be able to date Yamada if her love confession fails.
 * Future Yamada reveals in Chapter 44 this is his main intention.
 * : It seems Yamada's first dream is one of these.
 * Shameless Fanservice Girl: Dialogue in chapter 49 by Yamada heavily implies his mother is one of these, with all her swimsuits being pretty skimpy bikinis.
 * Sweet Tooth: Nori likes sweets a lot, to the point her mood quickly becomes better once she eats them.
 * Teacher-Student Romance:
 * Yamada thinks Chika and Shibata had one at first. He is quickly proven wrong.
 * Miki and Shibata are much more of a straight case.
 * Time Paradox: Openly discussed in chapter 16, with the characters discussing if they can indeed change their own actions with time travel without running into this.
 * Title Drop: Chapter 43 reveals that Lagoon is the name of the island.