Neon Genesis Evangelion is a manga and a animated TV-series made in Japan in the 1990s. The basic storyline is set in the future after the mysterious "second impact" which killed off a large part of the human population. Some time after the impact Earth was attacked by powerful monstrous beings known as "angels". Giant biological robots called Eavngelion (Evas) are defending the Earth against the angels. The Evas are piloted by children with nerve-systems compatible with the Evas. The story revolves around Shinji Ikari who is to pilot one of the Evas.
The story is complex and simple at the same time. The basic plot is a battle between humanity and aliens. But there are also many thing never fully explained like the mysterious organisation "Seele" and the "Human instrumentality project". And one of the charms is the use of gnostic/religious symbols ("The Golgatha Project", "Spear of Longinus", "angels" etc). This makes Evangelion re-watchable and gives it character. Also, the imaginative work is incredible with fantastic designs for robots and aliens, and a whole city called "Tokyo 3" with skyscrapers able to withdraw underground and form an inverted city. The battles between the angels and Evas usually take place in Tokyo 3. There are also references to older japanese pop-culture stuff. Like the "Super Robot" genre (Mazinger Z, Getter Robo etc). Just like in Mazinger, the robots need young people to pilot them. And just like in Mazinger the aliens attack one by one, one at a time, with the robots coming up from the underground to meet the challenge. There is also the usual anime mix of cuteness and violence, but beware because Evangelion is not for children.
"Evangelion 1.11 You Are (Not) Alone" is a movie version concentrating several episodes from the original, and giving them slightly other storylines. As I see it this is an improvement, not least in graphics. Evangelion 1.11 looks incredible and considerably better than the original (and on Blu ray!). The downside is that the story is now concentrated which means that certain aspects or details are missing. I think that without having seen the original series this movie can be a little confusing. (Sometimes things go a little fast, for example: it's not very clear thet Eva 00 is protecting 01 with a shield under the attack from the 3rd angel). If you like Evangelion 1.11 you should consider getting the sequel: Evangelion 2.22 (a third film is being made as well). And if you haven't seen the original series it can be recommended.
Highly recommended. If you haven't seen Evangelion you have missed something.