( I should point out since the OOP doesn't make it perfectly clear, that the reason why the customer service woman tells him she's calling him in secret is that she got asked by her boss to terminate the call as they were chatting too long and isn't allowed to phone customers in private (and they really hit it off during their conversation earlier, both were really shy but you could sense there was a connection between them...
The reason why they talk about a secret book is that it is one of the items Zelda [the game character of the nintendo game he's playing] need to go back and pick up to be able to complete the level, and "the guardian" is of course the level boss Zelda needs to defeat to win the level...
The reason why she finishes the call with "inshallah" is that she knows his name is Khalid and that he is from Algerie or whatever, and it's only meant as her way to wish him good luck with the game, as in trying to speak his language to show him she cares about him and like him...)
