The narrative begins with an explanation of "Murder Mystery VR" (MMVR), a virtual reality game developed by Horakuti Technologies. This advanced VR technology directly stimulates the user's senses, creating a highly realistic experience akin to a dream. Players are assigned roles as either the detective, tasked with uncovering the killer, or the killer, who must evade detection. The game offers significant freedom but also presents challenges, including time limits and random role assignments.
The protagonist, Itsukushima Raimei, a programmer who worked on MMVR, logs into the game. He uses the alias "Lai" and has chosen a younger, more attractive avatar than his real-life appearance. His motivation for playing is twofold: to enjoy the game and, more importantly, to investigate a concerning report from a beta tester whose son's personality changed drastically after playing. Despite his company dismissing the concern, Lai feels compelled to look into it. He enters the game as a test player, using his developer privileges, to ensure the game's safety before its official release.
Lai finds himself in a single room aboard the spaceship "Heliopolis." He learns his role is "Detective" and that the game will span three in-game days, with the objective to solve a murder before reaching the next planet. The game's time limit is tied to the real-world duration of his physical body's sleep in a "sleep machine." During a briefing, he meets the other six passengers: a silver-haired woman named Eleanor, a flamboyant man named Hikaru, a girl named A-chan, a woman in a black dress named Usami, a punk-like boy named Yumeto, and a stoic, scar-faced man named Kuros. The ship's captain, Beryl Daora, a seven-foot-tall octopus-like alien, explains that the ship is on a test voyage and some passengers are Non-Player Characters (NPCs).
Lai explores the ship, visiting the mess hall where he encounters Merlin, a sentient plant-like NPC who serves as the cook. Merlin offers Lai a "special drink" which is disgustingly awful, but Lai manages to endure it. He learns that the ship was formerly a warship and that Captain Daora has a questionable reputation.
Shortly after returning to his room, an emergency alarm blares, signaling the start of the game's central event. Lai, Eleanor, and Hikaru head towards the control room. On the way, they find a cleaning robot, "Nai-bo," disabled. Hikaru, eager to reach the control room, abandons Lai and Eleanor to help the robot. Lai, however, chooses to help Nai-bo, which results in him being attacked and killed in the lobby.
Using his special ability, "Continue," Lai rewinds time to just before the emergency alarm. He decides to help Nai-bo again, which seems to prevent his previous death. He then proceeds to the control room with Eleanor and Usami, where they meet the other passengers. They discover the control room door is locked. Lai suggests consulting Merlin, the ship's cook and a neutral NPC, who grants them remote access to unlock the door.
Inside the control room, they find Captain Daora murdered, stabbed with a knife. The scene is graphically realistic, causing distress to the players. Lai, using his "Debug" ability, observes the scene and notes the lack of blood spatter, suggesting the killer was careful. The players agree to move to the mess hall for further discussion.
