One day, high schooler Mai finds a mysterious game called Nightmare—a popular game that you have to keep playing every day, or your body will slowly start to shut down. And she's not exactly a pro gamer. Still, in the hopes of beating the game completely, she joins forces with shy Asagiri and handsome-but-difficult Sugiura to form the Nightmare Strategy Club! (from Yen Press)

At the end of the 21st century, the Earth is almost entirely covered by water. Human/fish hybrids known as "Fish-Halfs"

The world's greatest exposition of the pirates, by the pirates, for the pirates—the Pirates Festival. Luffy and the rest of the Straw Hat Crew receive an invitation from its host Buena Festa who is known as the Master of Festivities. They arrive to find a venue packed with glamorous pavilions and many pirates including the ones from the Worst Generation. The place is electric. (Source: AnimeNewsNetwork)

When three high school girls on a school trip wake up, they find themselves on a strange uninhabited island...! Nanami, the class representative who cares about her mother, Masami who is the ace of the soccer club and has a good mood, and Honoka who is a popular idol and has a high pride. The three do not know each other even at the same school, but they gradually open up to each other through their lives on the island. But salvation does not appear out of nowhere. No one knows why they were brought here...

From the end of the Showa period to the beginning of the Heisei period. Toys, sweets, games and play ... A nostalgic era when various things jumped out and disappeared in every field.