Kodansha Comics publishes the manga in English and it describes the story:
Natsu, Lucy, Happy, Erza, and the whole Fairy Tail guild are back in action! And they’ve decided to tackle the “100 Years Quest” – a job no one’s dared take on since the founding of the guild more than a century ago. A mysterious town, a baffling spirit, a ghastly new enemy…and a brand new continent to explore. When you’re with real friends, the adventures never stop!
Ueda (Dr. Prisoner, Hajime Shachō Monogatari) launched the official sequel of Mashima’s original Fairy Tail manga in Kodansha‘s Magazine Pocket manga app on July 25, 2018. Mashima is providing the original storyboards for the manga, and Ueda is drawing the series.
Mashima’s original Fairy Tail manga inspired three earlier television anime (including a “final season” in 2018), two anime films, several original video anime projects, and spinoff manga. Kodansha Comics publishes the original manga and a number of its spinoffs in North America.
Source: Hiro Mashima Fan Meeting