SSSS.DYNAZENON

One day on his way home, a first-year student of Fujiyokidai High School named Yomogi Asanaka meets a mysterious man named Gauma who claims to be a “Monster Tamer.” Suddenly, a Kaiju and a giant robot, Dynazenon, appear. Yume Minami, Koyomi Yamanaka, and Chise Asukagawa also happen to be passing by, and together with Yomogi they are caught up in a battle with the Kaiju.

Synopsis from Anime News Network