Minato Kanishiro is a 2nd-year student at Ouka Academy in the small town of Utanami, where he lives alone with his younger sister Fuuka after their parents died in a plane crash two years prior. He learns that his childhood friend Kanon Hiiragi, who has spent years in various hospitals both overseas and in Japan, is doing well enough to return home for a while. However, as her parents also died in an accident, she has no home to return to, so the Kanishiros invite her to live with them.
While unpacking Kanon's belongings, Minato discovers a strange device called a Dream App, which contains a program wherein five AI-controlled idol singers named "Dream 4 U" (D4U) appear and promise to fight for Minato if he's ever in danger. That declaration holds true shortly thereafter when Minato and all of his friends are attacked by a strange monster shortly after Kanon's welcome party in a local park, where D4U is able to destroy it with their song.
What follows begins as a Slice of Life story between Minato and his circle of friends: longtime friend Yuno Wakatsuki, third-year senior Satsuki Tsushima, first-year junior Natsume Kurihara, the mysterious Akira Tabunoki, and best friend Makoto Asukaya, while rumors of the mysterious "X Virus" continue to persist throughout the month.
This game provides examples of the following:
- Anti-Frustration Features:
- Only the tutorial battle needs to actually be fought. The game allows any other battle to be skipped entirely while still earning full experience.
- The Chart shows all of the potential events for a particular day/choice and any unlocked one can be revisited at any time to allow for a different choice.
- Beach Episode: 10/14 takes place at the local pool. The character Minato hangs out with that day also sets their respective ending flag to secure their route if the other prerequisites are met.
- Bittersweet Ending: Several of the endings fall under this. Kanon dies in every True Ending that isn't hers, at least one of the main heroines is Killed Off for Real in every route, and Natsume forever loses her body in her Normal End.
- Satsuki's true ending has Fuuka, Kanon, and Yuno be killed by Minato in quick succession, which causes him to go into shock and ultimately forget the events of the route because of the trauma. It ends with him finally recovering from it, though it's unclear if he actually consciously remembers anything.
- "Blind Idiot" Translation: Not the main game as a whole - despite having a typo every few minutes or the occasional incorrect name as it doesn't harm the narrative - but the translations for the Album/Options menu options are definitely this. The dates for the second half are also listed wrong in the load screen, advancing one day per date change even when the narrative makes it obvious that up to even months passed by.
- Bowdlerize: The US version changed nearly all instances of "school" to "academy" and none of the characters' actual ages are mentioned to make everyone appear as college/high school students rather than high/middle school students. Considering Fuuka is as young as 14 or 15, this was presumably done due to age of consent issues.
- Censor Steam: The only thing protecting Kanon's modesty in the event where she nearly passes out in the bath and Minato rushes inside to check on her.
- Color-Coded for Your Convenience: The colors of the neckties and ribbons for the boys and girls' uniforms respectively are what differentiate their classes.
- Downer Ending: Most of the Normal Endings involve Minato having to Mercy Kill the heroine he fell in love with, resulting in a Heroic BSoD he never truly recovers from. Natsume's is the main exception.
- Guide Dang It!: The game does nothing to spell out the requirements between the Joint and Destruction endings if no character's specific route is chosen and both will likely be obtained by accident before figuring out the specifics. The Joint Ending happens if Minato completes none of the heroine's prerequisites while the Destruction Ending is if he completes a heroine's prerequisites but doesn't set her ending flag on 10/14.
- Jerkass: Pretty much all of the gymnastics team except for Yuno. They lead new potential team members on a Snipe Hunt to string them along only to reject them anyway (only Satsuki's interference saved Yuno's chance to actually join). Then, when Yuno becomes the star and helps start making the team famous, the rest of the members are instead jealous and indirectly take it out on Yuno by bullying her biggest fan to the point of her being Driven to Suicide.
- Leitmotif: All of the heroines have distinct themes that play during scenes that focus on them, including sad and romantic variations.
- Lighter and Softer: Akira's route is surprisingly this, showing the good of humanity and having Ratom take an active role in helping. Her true ending even has all non-Kanon heroines recover from their transformation and has everyone cured instantly.
- Multiple Endings: Each heroine's route has a Bad/Normal/True ending while the more neutral "Joint Route" has a Bad/Normal ending as well as one for Makoto.
- Off-Model: Some characters have rather...inconsistent breast sizes.
- Paranoia Fuel: Rampant In-Universe as the pandemic breaks out as people 1. Don't know who may be infected even after (provided they do, as some routes don't have anyone discover this knowledge) learning the virus only affects women. 2. Don't know exactly how the virus is transmitted. 3. When women who are infected will either die or go berserk.
- Product Placement: Dream 4 U is an actual thing.
- School Festival: Takes place on the last day of October, and is a combination of both a culture and athletics festival. Also the day everything goes wrong and the outbreak starts.
- Sliding Scale of Cynicism vs. Idealism: Varies greatly depending on the route, making it feel as if the game has a Katawa Shoujo-style design where each person writes their route independent of the other writers. This can be seen by comparing Akira's true ending to Satsuki's, as Akira has Dream 4 You revert the transformations of Natsume, Satsuki, and Yuno through the Power of Love, and kill the virus off for good. Satsuki has Minato attempt to revert the transformations of Fuuka, Yuno, and Kanon and fail to do so, putting him in the hospital and not functioning at all due to the shock of ultimately killing his family and childhood friend. While Satsuki is cured, the virus is spreading far faster than it was before. Even the choices to get the true ending fall on the opposite ends of the spectrum. Akira's has you decide to destroy the virus to save everyone and Satsuki's has you vow to save specifically her from the infection, rather than saying you'll save everyone.
- Rhythm Game: Fighting in battle involves pressing specific buttons in time to the music to strengthen D4U's attacks. Although calling it a game may be too generous with how low effort it is.
- Serious Business: The girls joining the scavenger hunt in "The Sports Festival" bonus event for the sake of the Accounting Club's legendary double-cream doughnuts!
- Slice of Life: The first half of the game follows Minato's routine as he hangs out with various friends and builds relationships with the chosen heroine.
- World of Buxom: Outside of Satsuki and occasionally Kanon, everyone has a massive chest.