The Steins;Gate 0 (シュタインズ・ゲート ゼロ Shutainzu Gēto Zero ) anime is an adaptation of a spin-off visual novel by the same name that is being marketed as a "true sequel" visual novel, as opposed to being a fan disc. However, though Zero is part of the main canon, it is narratively not taking place after the true ending of the original story but technically before said ending. Zero is a side story that explores events from the Beta Attractor Field's future that contribute in making the end of the original story possible.
The visual novel was released in Japan on December 10th, 2015, in Europe on November 25th, 2016 and in US on November 29th, 2016. On March 28th, 2015, Chiyomaru Shikura, executive director of Mages. Inc., held a TwitCast, in which he announced that the visual novel's anime adaptation has already been greenlit. While no specific broadcast dates have been revealed, on July 28th, 2017, the revelation of a broadcast projection aiming toward the Spring 2018 (April). The anime series itself will have 23 episodes with an OVA bundled along with it.
The opening theme song is "Fatima" sung by Kanako Itō, who previously performed the opening song "Hacking to the Gate" in the original anime series. The ending song is "LAST GAME" sung by Zwei. "Amadeus" who also performed by Kanako Itō from opening of the Steins;Gate 0 visual novel making an appearance at the end of first episode of the Steins;Gate 0 anime series. Also "Lyra", ending song performed by Zwei making an appearance at the end of the eighth episode.
Zero takes place starting in November 2010 in the Beta Attractor Field outside of the Steins Gate. It depicts the Rintarou Okabe who had given up on saving Kurisu Makise after his first horrific failed attempt. Caught in despair, Okabe abandons his "Hououin Kyouma" persona and is tormented by flashbacks of Kurisu's death and the incidents of the Alpha world lines. The Labmems are worried about him, and at Mayuri's recommendation he begins treatment at a mental health clinic.
His life is stirred up again when, while helping out at a university seminar, he meets Kurisu's professor and research supervisor, Alexis Leskinen, along with Leskinen's assistant, Hiyajo Maho. Kurisu had worked in the same lab as them at Victor Chondria University studying artificial intelligence. From them Okabe learns about the "Amadeus" system, which stores the memory of a human and creates an emulation of that person. His life is changed completely when Leskinen asks Okabe to become a "tester" in interacting with Amadeus and Okabe meets Kurisu's "Memories" held within the system.
As a tester Okabe continues to speak with "Kurisu" using a dedicated smartphone application. As their conversations pile up, like in the past Okabe begins to grow closer. However, Okabe is also filled with anguish.
Other plot points include, the labmems hold Christmas and New Year's celebrations to hearten and cheer Okabe up. The girls dress as Santa Claus and shrine maidens and attention is given to the story of Amane Yuki and Daru and their future daughter Suzuha.
Also, while the Labmems are all gathered, a mysterious masked group bearing firearms attacks the lab, and Okabe is struck by the recollection of Mayuri's many deaths in the Alpha world lines. This is a world line where the PhoneWave no longer exists, and there should be no other reason for SERN to target them, but... 
Though it will draw from the Epigraph Trilogy light novels and the stories from various drama CDs, Zero is not a "game-ification" of those stories but will have its own new scenario. Characters not seen in the original visual novel and anime will also be joining the cast, such as Hiyajo Maho, Amane Yuki, Shiina Kagari; Fubuki (Katsumi Nakase) and Kaede Kurushima, Mayuri's cosplay friends; Alexis Leskinen; and Judy Reyes, a professor of physiological psychology.
The teaser for Steins;Gate 0 was released on July 28th, 2017. It's giving us a recap of the events leading to the main story whilst giving fans more information on the project at hand.The first PV trailer with shots from the anime also revealed the premiere of the anime to be in Spring 2018 (April). A second PV trailer is released a few weeks before the premiere:
|##||Episode Title||Release Date|
|Prequel||December 3, 2015|
|Sequel||"Polymorphic Valentinus -Bittersweet Intermedio-"|
"Kesshō Takei no Baarentinusu" (結晶多形のヴァレンティヌス)
|December 21, 2018|
- ↑ 1.0 1.1 http://steinsgate0.jp/ (Japanese)
- ↑ http://www.famitsu.com/news/201506/25081819.html (Japanese)
- ↑ http://www.animenewsnetwork.co.uk/news/2015-03-28/steins-gate-0-follow-up-game-and-anime-announced/.86470
- ↑ http://www.crunchyroll.com/anime-news/2017/07/28/more-info-on-steinsgate-0-anime-manga-and-novel-plans-revealed?utm_source=community_cr&utm_medium=facebook&utm_campaign=news&referrer=community_cr_facebook_news
- ↑ https://animemojo.com/seinen/steinsgate/steins-gate-0-anime-listed-with-24-episodes-but-not-all-of-them-will-air-on-tv-a4037
- ↑ http://gematsu.com/2015/03/steinsgate-0-announced
- ↑ http://game.umimi.com/archives/k_4537147087.html (Japanese)
- Crunchyroll News - "Steins;Gate 0" Anime Lines Up April 2018 Premiere by Joseph Luster December 14, 2017 7:37am PST
- TwitCasting - Shikura Chiyomaru's recorded live TwitCast announcing SG0 and anime 3/28/2015 3:59:12 AM