There's also a Wikipedia article, under its international title, Faithful Elephants.
Basically it's about 3 elephants at Tokyo's Ueno Zoo attempting to stave off being poisoned by the zookeepers while Tokyo was being bombed at the end of World War II.
Wahhh!All I did was read to her from this book...Oh, you don't have to be so reserved...Ku ku ku ku ku...I'm gonna tell Sakuya about this!The Poor ElephantOh, come on...Ultimate Sadistic Purple Bean Sprouts*hic**hic*Ku ku ku ku...You can't make Flan cry—!That made-up story isn't sad in the slightest!It's not sad, so stop it!Ku ku ku ku ku...What have you done to Flan!?Guardian MistressAh... Oneesama...