I think we know what the pitch for "Endgame: The Calling" was: It's like the Hunger Games, but without the realism! And there are PUZZLES! And a fetch quest! 
 And sadly, the pitch is all there is to recommend the first book of James Frey and Nils Johnson-Shelton's new series for young adults. The actual execution is like a piece of stale pizza with no sauce -- dry, flavorless and kind of tedious. In addition to the awkward, lifeless writing with its short bland sentences, the characters feel more like game pieces than actual people. 
 The premise is that there are twelve ancient lineages who have been preparing to save the world for thousands of years... and for some reason, only one person is eligible per line, even though any one person from thousands of years ago is going to have a LOT of descendants. And for some reason, only teens are eligible, even though you would expect people at their peak physical condition to be chosen. But what do I know? Endgame! 
 Now meteorites are falling on whatever city the ONLY appropriately-aged descendants are living in, signaling the beginning of the vaguely-defined Endgame. Every one of them has been trained in deadly Special-Ops-style combat, so they can kill anyone who gets in their way -- including each other. Their goal: when Endgame starts, they must fetch three keys. And so begins a world-wide, bloody quest for the Great Puzzle of Salvation. If they don't win, they die. 
 "Endgame: The Calling" is the worst kind of story -- the kind of story that has a brilliant premise... and falls flatter than a tortilla that has been run over by a steamroller. In the hands of a better writer, this would be an epic story. It has backstory that spans all of human civilization, sci-fi/fantasy "Sky People" who have caused all this, a large cast of characters who come from all across the world... it sounds very epic, and a writer like Brandon Sanderson or Garth Nix could have spun a spellbinding tale. 
 But do we get an epic story? Alas, no. It feels like neither Frey nor Johnson-Shelton even cared. 
 The biggest problem is the writing, which is as dry and bloodless as a mummy. Often it feels like a screenplay ineptly transformed into a novel -- most of the time, we're simply told the characters' actions and some bland inner descriptions like "she wanted this" or "he didn't like this." 
 Everything is related in short, clunky sentences in the present tense (presumably a failed attempt at immediacy). They're strung together like dreary little beads ("It's just a gash. It will need stitches, though"), and they never swirl up the passions of the reader. For instance, once scene involves Sarah cheating on her Perfectly Perfect Ken-Doll Boyfriend with one of her rivals, whom she is competing against. How is this conveyed? 
 "But then they kiss. 
 And kiss. 
 And kiss. 
 And Sarah forgets." 
 Riveting, isn't it? The heat just radiates off the page. 
 And Frey and Johnson-Shelton utterly fail at creating any sense of actual tension. The first few chapters contain devastating meteorite strikes that leave countless people dead... and the reaction of all the characters is either glee or dull surprise. Even when a character's brother is impaled on a steel beam and dies in front of her, she barely even seems to care. It's presented in such a dull, vague way that nothing actually seems important. 
 But that's because these are not characters. They are chess pieces. They are video-game avatars. The backstory, personalities, and experiences of the characters are nonexistent except for their Endrame training. Admittedly it is difficult to flesh out such a large cast, but some of their introductory chapters are only a few pages long -- just long enough to establish the character's nationality/ethnicity, and that they are a main character. 
 What is there to these people other than their nationality/ethnicity and the fact that they have trained to be in Endgame? Not much. Only one seems to have an actual life outside the Endgame prep, and that is just so her blandly perfect boyfriend can eventually be imperiled. 
 "Endgame: The Calling" has a shell of a plot, full of the characters' actions and words, but without any kind of narrative soul. The writing is dry, the characters are like paper, and the authors clearly cared about nothing but the movie rights.