Root Letter is a mystery visual novel developed by Kadokawa Games for PlayStation 4 and PlayStation Vita. The title was released in Japan on June 16, 2016 and was published the same year in North America and Europe by pQube. A port for the PC was later released by Kodokawa Games in 2017 and an enhanced version called Root Letter: Last Answer was published in 2018 which included an option to play the game with live-action photographs instead of illustrations. A follow up to Root Letter was released in 2020 called Root Film which stared a totally new cast solving a new mystery.
The game follows a 33-year old man named Nakamura Takanori investigating the disappearance of his old pen pal from high school, a woman named Fumino Aya. After loosing contact with Aya more than 15 years ago, Takanori happens to discover Aya's last letter she sent him that contains a farewell message and a confession to committing a murder. Now Takanori must go to Aya's home town, question her friends from high school, and use her old letters to find clues behind what happened 15 years ago.
Several former Konami employees who had previously worked on the Love Plus franchise, including character designer Mino Taro, developed Root Letter. The game was planned to be the beginning of a series of visual novels called Kadokawa Game Mystery. The idea was that each installment in the series would treat their characters as if they were being played by actors and actress with each game in the series having the same stable of talent playing new characters, similar to Laura Harris or Osamu Tezuka's Star System. For example, Root Letter's main heroine is "played" by a fictional actress named Aya. However, the second installment in the Kadokawa Game Mystery series, Root Film, ended up obfuscating this idea and instead just introduced totally new characters unrelated to Root Letter.