For the first time, Krypto appears, but isn't featured on the cover. Maybe Superboy is jealous and afraid he might get replaced. But then why does he tell us this story, in his own words? The whole thing is suspect, frankly.
It starts with Krypto returning to Earth and proceeding to play with Superboy, as normal, until the Boy of Steel gets a piece of green Kryptonite falls on his cape in a cave. Powerless and prone, Superboy shoos his dog away while he tries to think of a way out. Uhm... unclasp the cape and crawl away? Krypto can't even go get people to help, because of all the molten lava. Lava?!