In a beautiful seaside town on the Shima Peninsula of Japan, 11-year-old Toru Aizawa has lost his mother. In his sorrow, he stumbles across a tiny egg on a mysterious red stone, and the egg hatches into a cute turtle he names Toto. Mai, a friend of his with heart problems, suggests that Toto has something to do with Gamera, a monster that emerged 33 years ago and died defending the human race. Toru's turtle lives up to that when, after being missing awhile, it reappears to drive away a giant lizard monster. Knowing the threat will return, the Japanese government masterminds a defense strategy, but only Toto can stop the horrible monster.