Shinji tried to save Kaworu. He tried to save the world. He tried to gain his father's affection. All failed, and he unintentionally set off the Third Impact, and was absorbed into Evangelion Unit-01. When he came to, he was alive, and so was everyone else. They found themselves on a giant ship, with alternate versions of themselves. Their alternates explained that there was a crack within the multiverse that threatened to completely destroy every dimension in existence. Taking shelter in an undestroyed dimension, the Children will have to once more pilot their Eva's and face new threats in hopes of saving the entire Neon Genesis multiverse. (I don't own Neon Genesis Evangelion)