This is a review, so there is spoilers..
Good premise, and alot of action, but goes down hill in second half when plot becomes ridiculous.
The Tomorrow Code is a young adult apocalypse novel about two kids in New Zealand who stumble across information from the future that the world will end soon. Like The Di Vinci code, action and plotting hide several large plot holes. This is a time travel story where two fourteen year-olds get information from the future sent by their future selves. It is never really explained how they discover how to send messages, and the whole thing is circular, they get messages from the future telling themselves how to build a machine to send messages back in time, so they do which allows them to send their past selves this knowledge (They actually name a sub they buy Mobius as this concept is called a Mobius strip) Neither of them have the technical know how to construct it and a friend builds it for them in the past..so how they know how to build it to tell their future selves in a plot hole big enough to drive a truck through. It also is unstated what makes them of all people so special to be placed in this Mobius strip, they are fourteen although the girl Rebecca seems to have alot of knowledge way outside the norm for a young girl. (the author gets this out of the way by stating she is a genius.) Its reminiscent of "Groundhog day" but end of the world style. But unlike Groundhog day, where the main character is pulled into the Mobius because he is a jerk and must see true love, there is no explanation for why these to kids get sucked into the loop. Its a big missing piece.
Also, the environmental message is laid on very thick and beats one over the head. The girls human self loathing/hatred (thinks we all should die) is good for the plot, but comes out of left field. A fourteen year old isn't that fatalistic without explanation, and the book doesn't invest the character with the motivation to make her views a natural outgrowth of her character.
The threat to humanity, when it presents itself, is rather absurd (we are powerless to fight an enemy that can be destroyed by..water, huh?) Although not having enough firetrucks handy when it gets out is understandable and was a good action scene and the sense of action and lost cause hopelessness of being out gunned and out manned was a page turner, wouldn't the rest of the world easily stop the threat once they had more time to prepare?
For young adults, its a decent read, especially for teenagers who like end of the world yarns. It has a chaste love story with two brothers competing for the girl and the kids are of course smarter than all the adults. However, for adults, once the "big reveal" in the second half of the book is sprung, the plot holes may make this a slog. However, I did read the whole thing, which shows the book is a page turner and is action packed. The New Zealand setting was different and I enjoyed the cultural flavor the setting provided. But the absurdity of the plot and the ham-fisted environmental message had me skimming the last hundred pages just to see how it ended.