Ren Homura has just returned to his hometown after a lengthy absence with no memories of the place. After being forced to replace his smartphone after an accident, he finds himself caught up in a game where monsters are summoned to do battle against one another… a game which seems to be related to his lost memories.
For the most part this is not a serious show and plays just about everything for laughs with a random sense of humor; it’s only in the last quarter or so it becomes a full battle shounen. It’s also shorter than the episode count would suggest, as each is only ~7 minutes long. Episodes with longer runtimes are padded with advertisements for various things related to the game and Anime.
More Information:
aniDB
Crunchyroll
Wikipedia