"Super-Frog Saves Tokyo" is contained in his anthology of short stories "After the Quake", whose theme is the Great Hanshin-Awaji Earthquake in 1995. The stories in this anthology don't tell about this earthquake directly, but make the readers think of it deeply.
"Super-Frog Saves Tokyo" is an allegory. Super-Frog is fighting a great earthworm under ground, which wants to cause a big earthquake in Tokyo. Super-Frog ask Mr. Katagiri, who is an ordinary "salary man" to help him fight the earthworm.
I'd like to quote the impressive part of this critic as follows.
In the story, Super-Frog tells Katagiri that "in all of Tokyo, with its teeming millions, there is no one else I could trust as much as you to fight by my side." Katagiri insists that he’s a less-than-ordinary man. "I live a horrible life. … I don't even know why I’m living." he says. "Why should a person like me have to be the one to save Tokyo?" Super-Frog replies: "Because, Mr. Katagiri, Tokyo can only be saved by a person like you. And it’s for people like you that I am trying to save Tokyo."
When I suffered from deep depression (I have not made a full recovery yet), I really felt that I was a "less-than-ordinary man" and complete useless in this world. So I'm very impressed and healed by the words "Tokyo can only be saved by a person like you.".
I can't do much to save Tokyo and Japan now, but there must be something to do, which I can do. I remember my motto "I will just do what I can do.".