Gai is being a dick and proposing to kill all humans on Christmas eve (Oh here we go, another Lost Christmas hu?). Shu is somehow in a room with other people and nobody is punching him senseless. The past is finally explained, and its bloody complicated-
Things all started off with Shu's father and his best friend. These two guys are researchers. They studied the Genomic Resonance Theory, which is something to do with natural selection and evolution.
Shu's father starts shagging some bird from the medical school and she falls pregnant with Mana, anyway they marry and move away.
Its now 5 years later and a meteorite falls on an island, found by Mana. It causes a genomic resonance reaction, which Mana got tied too somehow when she got pricked by it on her finger. The virus spreads across her body.
The two researchers find out the virus is only caused by 'genomic resonance', which is I think is caused by Mana herself. How? Its not explained.
Some boy called Yu turns up in a lab coat, who calls himself an envoy of Daath (da fuck!?) and tells the two researchers that they are screwed, along with the rest of the nation (and then the world?). He calls Mana the new 'Eve', and says that the fourth apocalypse will select those for the next evolution in life, but only once Mana is matured.
During this time, Mana chooses her unborn sibling to be her 'Adam'. Shu is born, and Manas/Shus mother dies in childbirth (from the virus).
The boy called Yu is cloned out of disgust from the best friend at the thought that both Mana and Shu share the same gene pool which will go on to repopulated the earth once everyone else is dead. (Who the fuck is this Yu bloke?!)
These clones are bred to withstand the virus. Anyway, Gai turns out to be one of them, and goes on to be the only successful living clone left, as all the other sucked and died from the virus.
Gai escapes the facility and jumps into the ocean, only to wash up on a beach where Mana and Shu are playing (THATS IT! I'm going home! wheres my coat and hat!?)
You know I said that originally there were two researchers, Shu's father and his best friend? Well the best friends little sister turns up and starts shagging Shu and Manas father, a widower who has just lost his wife for fuck sake!
She becomes Shu's and Mana's adopted mother.
Ok so just before Lost Christmas, the best friend is fed up of being his best friend and shoots Shus father dead. Not surprising really. This may be what triggers Mana into causing Lost Christmas, and going all apocalyptic on everyone. As she does this, she scatters parts of herself into the public. These parts were later called 'voids'. all voids needed to be collected to resurrect Mana (into Inori).
Plot hole alert! How the fuck is every void going to be collected before Manas Resurrection? Remember,
As we know, when Lost Christmas happens, Shu forgets his memory of Mana trying to kill herself from the virus inside her. Gai, who also witnessed the event, went on to fight as a rebel against the government who held back secrets regarding the virus? I'm sorry something is wrong with this analogy, especially because back in the present day he ends up being all high and mighty when the virus takes over his mind (?) (much like it did with Mana?) (Am I along the right tracks here?). Talking of Mana, in the present day, somehow she ends up alive and tries to force her way into the body of Inori (a clone of Mana).
Why the fuck is Inori a clone of Mana again? Surly they would want to destroy the alien virus, not do everything in their power to ensure the total eradication of the human race?
OK this is bollocks. back in the present day, just before Shu goes off to save the planet once more, he tries to shake hands with one of his friends who only a few episodes back couldn't give a fuck about under his dictatorship.
"No fucking way do I want to shake the cold hand of a fucking dictator scum!
You don't give a shit about me! Fuck off and die already!!"
This is shit. No amount of convoluted back story will hide the gaping plot holes.
The only cool thing about this show is the opening and ending themes. That's it.