A boy finds an unusual egg, from which a baby turtle hatches, some 33 years after Gamera self-destructed to destroy three Gyaos in 1973. It is the 12th entry in the Gamera film series, and serves as the second reboot of the franchise, with the first being Gamera: Guardian of the Universe in 1995.

References:
https://en.wikipedia.org/wiki/Gamera_the_Brave