User blog comment:Menara/The Son of Sobek: The official PJ and Kane Chronicles Crossover/@comment-5341032-20130427130423

--( Answer to the question below and  maybe SPOILER )

my friend. It's both.

Check in Amazon kindle, the book is available for pre order.

it is also behind the serpent's shadow book, but if u already bought the book. you need to buy the 40 paged short story. About 5 dollars.