Ef: A Fairy Tale of the Two is a two-part Japanese adult visual novel series by Minori for Windows PCs. The first game in the series, Ef: The First Tale, was released on December 22, 2006, and the second game, Ef: The Latter Tale, was released on May 30, 2008. The opening video for the game was animated by Makoto Shinkai, and a majority of the music was produced by Tenmon, who has worked in the past with Shinkai and Minori. Female character design was by Naru Nanao of Da Capo fame, while male character design was by 2C Galore.
Before the release of Ef: The First Tale, a manga based on the overall story was serialized between 2005 and 2015 starting in Dengeki Comic Gao, but later transferred to Dengeki Daioh. In addition, a light novel was serialized in Kadokawa Shoten's Comptiq from July 2006 to July 2008. A 12-episode anime adaptation titled Ef: A Tale of Memories was produced by Shaft and aired between October and December 2007. A second season of the anime titled Ef: A Tale of Melodies aired 12 episodes between October and December 2008.
On September 26, 2010, it was announced that MangaGamer had acquired the rights of the visual novel for a worldwide English release, in partnership with the translation group No Name Losers. The English version of the two games were released in 2012 and 2013. The license holding company Sentai Filmworks licensed both Ef anime series.
On Christmas Eve, Hiro Hirono's bike is stolen by a girl chasing a thief who stole her purse. He gives chase and finds her unconscious and his bike ruined. The girl, Miyako Miyamura, soon awakes and the two begin to talk. After making sure she is okay, they end up spending Christmas Eve together. Later, Hiro finds out Miyako attends the same school as him and they begin to spend more and more time together, Miyako developing affections for Hiro. Kei Shindou—Hiro's childhood friend who has long held a crush on him—begins to become jealous and a love triangle follows.
The series also tells the story of Renji Asou. One day, he meets Chihiro Shindou, the twin sister of Kei Shindou, at an abandoned train station. Even though she's very shy, they get along pretty well and begin meeting at the same spot every day; however, Renji finds out that Chihiro was in a car accident years ago and as a consequence she suffers from a disability: her memory lasts only 13 hours. Nevertheless, after learning that Chihiro's dream is to write a novel, Renji finally decides to help her fulfill her dream while also trying to make her overcome the difficulties imposed by her condition.