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, 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 in, however, things take a highly interesting turn.
Includes examples of:
- A-Cup Angst: Nori's reaction, when she realised that Chika's deep cleave wasn't even supported by a bra.
- Accidental Pervert: When Yamada and Chika meet.
- Blind With Out Em: Chika. A rare played for drama example. Chika lost her glasses when she fell off the ship. The main reason Yamada didn't confess to Chika while they were alone, was because he thought she'd have no choice but accept, because she wouldn't have been able to survive on her own due to her poor eyesight.
- Cassandra Truth: Nobody believes Yamda's talk about a mysterious island when he gets back to civiliation naturally so he has to go back him self to rescue Chika and Shibata.
- Chronic Hero Syndrome: Yamada shows hints at this.
- Crash-Into Hello: Well, technically, the collision happened shortly after they met.
- Deserted Island
- Engrish: The title. Ow. note
- In Medias Res
- Jerkass: Shibata
- Love Triangle: Nori->Yamada->Chika
- Never the Selves Shall Meet: When Yamada comes back to the island, he arrives at a point in time where his past self as still inhabiting the island, he resolves to avoid this.
- Averted. Turns out that the two Yamadas did/will indeed met each other. They met when back in chapter 5 when(Past)Yamada took a nasty tumble. (Future)Yamada took the opportunity to give... er, himself... some advice, knowing that his past self would think that whole encounter was a pain-induced hallucination.
- Pun-Based Title: The title is a pun off of the japanese phrase "Let's La Go" (レッツラゴー).
- Time Travel: It seems the fog surrounding the island can cause this.
