Innocence as a theme is clearly related to the character of the son, who, no matter how devastating the world around him, continues to cling on to some sort of moral code where he believes, or wants to believe at least, in the intrinsic goodness of man. The father finds himself in a very difficult position, as he needs to act in ways that are morally questionable in order to save and protect his son whilst at the same time trying to retain his son's fragile sense of what is right and wrong. However, the son's innocence is clearly displayed through his reaction to what happens to them. Note, for example, how when they discover the bunker with the amazing supply of tinned food within it, he asks if it is alright for them to eat it. Then, when they have their first meal, he tells his father that they should thank the people that stored the food they are going to eat. Note how he does this:
The boy sat staring at his plate. He seemed lost. The man was about to speak when he said: Dear people, thank you for all this food and stuff. We know that you saved it for yourself and if you were here we wouldnt eat it no matter how hungry we were and we're sorry that you didnt get to eat it and we hope that you're safe in heaven with God.
On the one hand, there is a touching simplicity to the boy's prayer of thanks that clearly displays his innocence and his determination to cling on to a moral code that the world seems to have abandoned. On the other hand, such a prayer portrays the boy as being rather naive and simple in the way he looks at the world, which, both to the reader and the father, is so tragically different that no matter how hard the boy tries to pretend that there are clear "goodies" and "baddies," the lines between these two discrete categories are obviously blurred and indistinct.