Years after the Fourth Holy Grail War, Waver Velvet becomes the head of the Modern Magecraft Theories department at the Clock Tower, succeeding the title of Lord El-Melloi II. Waver and his apprentice Gray set out to find the truth behind a mysterious shadow that stalks them, while trouble brews among the mages of the Association. [Written by MAL Rewrite]

This episode takes place before the actual planning of the School Fair and shows how the girls spend their summer holidays.

On their way back from the 18th floor, Hestia, Bell, and the others accidentally uncover a hidden, mystical hot spring, and they decide to stop by to refresh themselves until creatures lurking in the dark appear to attack them.

Doraemon: Nobita no Takarajima takes the well-known characters to the Caribbean Sea; Nobita is the captain of a ship and fights against his enemies. Shizuka is kidnapped and a storm prevents her persecution. When the adventurers finally find the mysterious Treasure Island, where they have taken Shizuka, they discover that it is something more than a common island.

(Source: Official Website)