Kane Blueriver and his AI companion Canal Vorfeed are trouble contractors, taking on jobs that require their special skills. Their jobs vary from armed escort, to patrol duty, to the capturing of dangerous criminals. Millennium Feria Nocturne is a private eye who has to be the best at everything.

When the three of them get together, they run into one mess after another, gradually uncovering more of a mystery that ties the legendary Lost Ships to all of their pasts, bringing them closer and closer to a discovery that something called Nightmare would rather not have them find...

After moving into the quiet town of Hinamizawa, Maebara Keiichi spends his days blissfully in school often playing games with his local friends. However, appearances can be deceiving. One fateful day, Keiichi stumbles upon news of a murder that had occurred in Hinamizawa. From this point on, horrific events unfold in front of Keiichi, as he soon learns his close friends may not be all that they seem.