In ages long forgotten, when Earth found itself on a collision course with a meteor, Legendary Pokémon Arceus used its power to avert the danger. However, this feat caused the 16 Plates surrounding it to scatter across the world. Without the Plates providing Arceus with life energy, it began to die. A human named Damon managed to find one of the Plates and returned it to the moribund Pokémon, helping it recover. As a reward, Arceus created the Jewel of Life and gave it to the people of Michina Town, stipulating that it must be returned, but the humans refused, hogging the Jewel to themselves. In the battle that ensued, Damon was killed and Arceus went into slumber, vowing to punish humanity upon its return.

Satoshi and his companions arrive in Michina Town where they come across Sheena, a descendant of Damon, who claims to be in possession of the Jewel of Life and intends on giving it back to Arceus when it awakens.

The situation takes an unexpected turn when Arceus, despite Sheena's best intentions, remains unsatisfied. Satoshi must now prevent the destruction of the entire human race, as Arceus' fury causes distortions in the fabric of the universe, enraging the Legendary trio—Dialga, Palkia, and Giratina—and disturbing the world's balance.

[Written by MAL Rewrite]

A hundred years after catastrophic shifts in tectonic plates caused most of its area to submerge, Japan now thrives as a maritime nation. High functioning cities line the coasts of Japan, and well developed sea routes are defended by specialized naval ships. The marine industry is flourishing, and young girls are eager to join the Blue Mermaids—highly skilled women who devote their lives to protecting the seas. After some time apart, childhood friends Akeno Misaki and Moeka China are reunited at Yokosuka Girls' Marine High School. Here they are joined by others who share their dream of becoming Blue Mermaids. Soon, training exercises commence, with Akeno and Moeka being put in charge of their own ships and crew. Everything is progressing smoothly for Akeno as she settles into her role as captain and builds camaraderie between her fellow crew members aboard the Harekaze, a destroyer ship. However, unexpected engine and navigation failures soon leave their ship stranded and the crew in danger. High School Fleet follows the Harekaze's valiant crew as they navigate treacherous waters and other obstacles on their quest to become fully fledged Blue Mermaids. [Written by MAL Rewrite]

The story is set on Okinawa's isolated island of Iwado, which has seen a growing movement advocating a return to an autonomous government. Ao Fukai, a 12-year-old boy with a missing father, lives on the island with an old doctor named Toshio and is about to enter middle school. Ao's mother was taken away a decade ago by unknown individuals. Naru Arata, Ao's 12-year-old childhood friend and the story's heroine, lives with her father, older sister, and grandmother. She has a "Yuta" power awakened within her due to an incident when she was young. A mysterious entity called "Secret" suddenly appears and launches an attack on the Scub Coral lifeform on the island. Ao launches a certain military FP called "Nirvash" aboard a Japanese military transport in his fervent desire to protect the island. (Source: FUNimation)

The gang goes to an indoor swimming pool for some fun in the sun. As expected, all hell breaks loose when Tomoki goes on one of his perverted missions. Meanwhile, Nymph is having some issues with the loss of her master and considers asking Tomoki to be her replacement master. This episode was not aired on TV because it was deemed too dangerous...