Its story is about the protagonist. Kazuha, and her childhood friend Hiroya, looking for her brother, Shiki, after he went missing. Over in his apartment, they discover that he's been playing a new MMORPG, Arcadia: upon logging in to discover clues about his life there, they instead find themselves transported into the world of the game, and apparently have no option but to finish it all if they want to come back to the real world alive.
It's not all bad, however, as Kazuha soon finds herself referred to as the "Almighty", and realizes that the circumstances of her arrival provide her with a unique power that is highly sought after by the other players.
The visual novel contains examples of the following tropes:
- Absurdly High-Stakes Game: If you die in the game, you die in real life.
- Artificial Intelligence: Zain.
- Bishōnen: Combine with Cast Full of Pretty Boys.
- The Cake Is a Lie: The creator promises that beating Ark means returning to your regular life, but this is a lie. See also Unwinnable by Design.
- Cast Full of Pretty Boys: Played straight by most of the cast but subverted in that this is an otoge with a dateable girl, Libera, and a mascot-like character, Poyo-Poyo. Double subverted in that both characters are pretty boys in real life.
- In Medias Res: The game begins with your character trying to escape a monster inside Arcadia, before flashing back to how she ended up there in the first place.
- Interface Spoiler: Only romanceable characters show up under the "Status" menu, which can be a spoiler if the player is unaware that Demento can be romanced.
- Put on a Bus: Often happens to Hiroya in routes that are not his own.
- Unwinnable by Design: Ark is actually designed to be the dying place for the strongest souls for the Period Cube.
- Win to Exit: The game states that, in order to return to your regular life, you can temporarily do so my completing special quests or permanently do so by beating the final dungeon, Ark.
- Year Inside, Hour Outside: An hour outside of the game is approximately a day in the game.
- Your Mind Makes It Real: Invoked in the game when they brought up that the food you taste in World V is likely simulated from your memories.