Check the covers. There. You know at once whether you want to read this or not. The thing is, why wouldn't you want to read a story about a giant, genetically tricked-out T.Rex stomping around London, particularly one written by a fellow like Sam Enthoven? Of all the writers of young adult SF/fantasy who've popped up in recent years, Enthoven is the one who most unabashedly wears his inner geek on his sleeve (the sleeve itself most likely attached to a frayed and faded C3PO t-shirt dating to 1980). Video games, graphic novels, Japanese rubber monster movies, and way too much high-sugar cereal are the cultural tentpoles of Sam Enthoven's life. If you asked him to whistle the theme music to Land of the Lost, he could probably do it. And he brings his love of adolescent junque culture to life in his own storytelling with an enthusiasm you can't help but admire.

Unfortunately, that's really all he brings to Tim, Defender of the Earth. Enthoven's storytelling has a carelessness we never saw in his estimable debut, The Black Tattoo. I know it must seem the height of foolishness to critique a story all about a giant T.Rex stomping around London on the grounds of plausibility. After all, you wouldn't read this sort of thing in the first place if you didn't expect it to be deliriously silly. But even the most outlandish escapist fare needs to follow a tidy internal logic within the context of the world it creates. This is where Enthoven fumbles the ball. The knocking-over-buildings scenes are every bit as smashing — in the literal sense — as you'd hope to see. It's in establishing a convincing narrative framework to support them that the book is weaker.

It's like this: the British government has been secretly funding a program to design a genetically-enhanced supersoldier that has, quite reasonably, produced a Godzilla-sized T.Rex. They call him Tim, which stands for Tyrannosaur: Improved Model. Tim is kept in a huge underground bunker 70 stories below London, and Enthoven, perhaps wisely, doesn't explain exactly how they feed him, let alone clean up his poo. There's such a thing as too much information.

When unctuous Prime Minister Sinclair, a hilariously on-the-nose sleazy politician, takes one look at Tim, he spends approximately five seconds being suitably awed, then informs Tim's handlers that, while a big dinosaur is neat and everything, he really can't see any practical application for Tim in a defense sense. The point is well taken, I must admit. Sinclair tells Tim's handlers their funding is being cut off and diverted to another secret project, and orders Tim destroyed. When they start pumping cyanide gas into Tim's chamber, the poor dino — hey, he never asked to be born! — realizes, with his genetically-enhanced brain, that he's in trouble, and with his powerful arms he digs his way to the surface. How he knows which way to go is one of those mysteries of giant-monsterdom that I suppose someone, somewhere has studied in depth. Probably in Japan.

Anyway, Tim bursts to the surface, wreaking entertaining havoc. Fortunately his hide is too thick to take damage from all those annoying missiles that keep being fired at him. If only these tiny frightened people would realize he meant them no harm and just wants to be left alone. So Tim tromps out of London, which returns, with surprising swiftness, to its daily routine after he's gone. You'd think the appearance of a dinosaur the size of Big Ben would dominate headlines globally for a whole year. But everything goes back to normal for some reason. It isn't until the next crisis arises that the world sees fit to take notice.

Remember that other secret project? Well, it's led by one Dr. Mallohide, who has perfected nanotechnology to the point that he's able to dissolve living things into their component atoms and then reconstruct them. It's too bad Sinclair didn't grow up watching the same monster movies Sam Enthoven did, otherwise he'd know that no one but a Mad Scientist would do something this weird in the first place. Like all Mad Scientists, Mallohide can't wait to try his little experiment on himself. Mallohide quickly transforms himself into a floating cloud of nanoparticles looming over London, snatching up and absorbing lifeforms — animals as well as unwitting people — into himself, all the while believing (as Mad Scientists do) that everyone is a bunch of fools for not recognizing his genius and the wonderful gift of post-human, godlike power he offers them.

Tim, meanwhile, taking refuge deep in the sea, has encountered the mythical Kraken. This avuncular tentacled beast informs Tim that he's inherited the Kraken's role as Defender of the Earth, protecting this fragile planet from out of control forces that would destroy it. (So there are green themes underlying all this monster mayhem, you see.) But Tim can't do the job alone. He needs help from the bearer of a special amulet with the power to bring to together the "life force" of every person in the world. This bearer is Chris, a sullen teenager whose only friend happens to be Anna Mallohide, our Mad Scientist's very own daughter. Tim undertakes his role as Defender with T.Rexish gusto, and tromps back to London. Now a mighty clash of the titans will determine the world's fate.

There you have it. As a tribute to Japanese moster movies, you could do worse. Enthoven naturally pursues the action scenes with glee, taking so much geeky joy in demolishing London's most famous historical landmarks — Big Ben, St. Paul's, Parliament, the Old Bailey — that he can't resist talking about just how historical and famous they are before reducing them to rubble. And you really do root for Tim, because his determination to fulfill his role as Defender is undertaken with something of a childlike, sweet naïvety, as if from someone who's decided they want to devote their life to good works — like a college kid signing up for the Peace Corps in a war-torn developing nation — without a proper appreciation of just how evil evil people can get.

But Enthoven's human protagonists are not as well-developed in their motivations or personalities as they were in The Black Tattoo. We're given an unsatisfyingly thin explanation as to how Chris's amulet was discovered, let alone the role played in the whole affair by the henna-haired British Museum guard who watches over it until Chris's arrival. And then Chris himself is a huge problem. Immature and petulant, he's so insecure and embarrassed by being thrust into the limelight during this time of crisis that he stubbornly refuses to act his role, risking the lives of everyone on Earth in the process.

Sure, I understand that Enthoven's point is to give Chris a character arc, so that he must overcome his fears and grow up in order to face his adult responsibilities to his fellow man. But going this route presents the plot with another logical flaw. Why would the Kraken create an amulet — actually it's a bracelet — intended to aid the Earth Defender at the time of his greatest conflict, only to have the one person able to activate it a whiny, self-pitying, self-absorbed adolescent who's easily mortified and solely concerned with his "cool" image? I'd think if the fate of the world were at stake, I'd have my magic item attach itself to the one person on the planet with his or her shit together better than any other fifty people combined. Certainly someone above voting/drinking age. Let the immature, leave-me-out-of-it teenagers grow up on their own time. (Though to be fair, Anna is entirely sensible and much more suited to the hero role than Chris — and having her be the amulet-bearer could have given the story stronger conflict, by making her go against her father even more boldly than she already does, by actively aiding his enemy.)

Yes, I know why Enthoven did this. His target audience are teen readers. So naturally he needs protagonists to whom they can relate, and your stereotypical square-jawed Bruce Willis clone ain't it. But where that ends up leaving Tim, Defender of the Earth is roughly at the same level of merit as the classic Toho creature features to which it pays tribute. Those old Godzilla and Rodan and Gamera movies have earned their place in cinema history for better or worse, and they will always have a loyal audience. Hell, I get a kick of them myself. But I suspect many of the fans who embrace those movies the most would be the first to tell you, sure, they're great fun — but you don't exactly watch them for Oscar-caliber scriptwriting.