√Letter is the first entry in the publisher’s new series of mystery games. It’s a youth mystery adventure set in Shimane Prefecture and features both adventure and simulation parts. Minoboshi Tarou, Love Plus' character designer that left Konami in March, is handling character designs and planning. The scenario is being handled by Fuji Dario, and the music is by Nitta Takashi.

√Letter is set in Matsue, Shimane Prefecture, where the protagonist arrives in search of Fumino Aya, a pen pal friend from high school who had disappeared for 15 years. After he finds a letter dedicated to him from her that was never sent, he sets out to interrogate her classmates as he wonders if everything Aya had told him had been a lie. The game contains multiple endings based on the player's choices throughout the game.

[Edited from Gematsu and Wikipedia]