Bekku Nanaki has just moved to Tokyo from her rural hometown and a boy called Banjou Kizaki saves her from a falling billboard. The next day, she discovers that they are classmates, and that he has a reputation for being involved in various accidents and all sorts of trouble. When he drops his notebook, she discovers the reason why he gets into so much trouble in the first place is because he has been making sure that they don't happen, due to his notebook giving him predictions about the various disasters. Bekku, at first, refuses to believe him, even going so far as to throw the notebook into a canal, but over time comes over to his side and reveals [[spoiler:that she too can predict the future using mirrors.]] Together [[TheyFightCrime they work to break fate]].

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This work contains examples of:
* ArtifactOfDoom
* BadAss: Banjou. Holy shit, Banjou.
* CassandraTruth: It's in the title. [[spoiler:The final chapter opens up with the Greek myth of Cassandra. By the way, Bekku was [[TheFatalist a fatalist]] at first because, due to this trope, her childhood friend Nao died because she didn't believe it when Bekku told her about her own death. This lead to Bekku believing that [[YouCantFightFate You Can't Fight Fate.]]]]
* ClockTower: the focus of Chapter 3.
* ClothingDamage: Banjou, and ''how''.
* {{Determinator}}
* DemonicPossession: [[spoiler: happens to those who wear Cassandra's Mask.]]
* DudeShesLikeInAComa
* GirlishPigtails: Chiasa.
* TheFatalist: Bekku at first.
* JustInTime
* LeeroyJenkins: because [[JustifiedTrope he knows that he won't die doing]] [[NormallyIWouldBeDeadNow those ridiculous stunts.]]
* LeftHanging: [[spoiler: The ending shows us at the day of Banjou's final prediction - his own death at the [[DangerousSixteenthBirthday age of 20]]. However, we do not find out if or how he dies.]]
* MakingASpectacleOfYourself: His glasses are hot pink.
* MagicMirror: [[spoiler: Bekku's prediction medium is a mirror, or rather, any reflective surface. Banjou once made her use the reflection of his eyes to see a prediction.]]
* MaskOfPower
* NeckLift
* NoHoldsBarredBeatdown: [[spoiler: Poor Banjou doesn't get much of a say in the final showdown between Bekku/Cassandra's Mask]]
* PillarOfLight: [[spoiler: When Cassandra's mask is destroyed.]]
* ScrewDestiny: the major plotline.
* ScryVsScry
* {{Short Runner|s}}: After eight chapters, it's done.
* TimeBomb
* TokenMiniMoe: Chiasa
* YouCantFightFate: The counter argument. [[spoiler:This counter argument is touted by Makita, who has a tape recorder telling him the exact details of what will happen. He gleefully takes it as a gift from the gods, sets himself up as a "prediction enforcer" and considers what Banjou and Bekku are doing as "unforgivable."]]
* ZettaiRyouiki: Almost anything Bekku wears. Then there's Chiasa...
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