What is the problem and solution in the book 39 clues book four if u read it

Beyond the Grave is the fourth book in The 39 Clues series first published in June 2, 2009 and written by Jude Watson.[1]Thematically the novel uses Biblical knowledge, prophecy, and spiritual topics to explore the afterlife. Amy and Dan Cahill, the protagonists, travel to Egypt because of a clue they discovered in The Sword Thief.[2] The symbols in the middle of the book translate "Alistair was there the night they died."

Beyond the Grave was awarded one of Good Morning America's pick for teen summer reading. [3]