World Trigger is a tV series anime that premiered in fall 2014, produced by Toei Animation.

About the production: the story comes from a manga, there are 73 episodes of about 23 minutes and its current status is "finished".

Its main genres are action and sci-fi, with themes such as Aliens, Shounen, Ensemble Cast and Urban Fantasy.

On AniList, World Trigger has an average score of 73%, a good score, and appears on 121,937 users' lists.

The franchise continues in or follows from: World Trigger 2nd Season.

One day, a gate to another world suddenly opens in Mikado City. Aliens invincible to Earth’s weapons, called “Neighbors”, start coming over. Earth’s only line of defense is a mysterious group called the “Border” who are armed with weapons called “Triggers”. Four years later, the city has recovered from initial attacks and citizens of Mikado City have started to get used to the Neighbor’s attacks. Yuma Kuga, a transfer student, and his classmate Osamu Mikumo find themselves fighting a Neighbor that suddenly appears. Osamu, who is actually a Border agent, activates his Trigger but is unable to defeat it. This leaves Yuma to activate his own Trigger and defeat the alien. Yuma reveals that he is not part of Border and is actually a Neighbor who has transferred from the other side. (Source: Crunchyroll)

Official synopsis from AniList.