This is the first in an expansive series of novels featuring as their heroine Riko Rinda, an appraiser with an incomparable gift for instantly seeing through all mitigating facts and circumstances to the true value and essence of whatever is presented to her for assessment.
The story begins in 2010. Yuto Ogasawara, 26, a reporter employed by one of Japan's biggest publishers, is up against a story deadline as he pursues the mystery of graffiti-like stickers, referred to at large as "sumo stickers" because they depict the figure of an obese man, that have been popping up in various locations around Tokyo. On a whim he decides to drop in at an office where the sign touts appraisals of any and all kinds. The beautiful Riko emerges from the back. After watching her summarily pronounce the painting brought in by the customer before him a fake, Yuto asks Riko to solve the mystery of the sumo stickers?and thus begins a Watson-and-Holmes?like relationship between the two.
Riko is looking for new office space she can rent in central Tokyo. She puts her name in for a bargain-rate property that is to be leased by lottery, but it becomes clear to her that the lottery is rigged, and she informs the police that the group linked with it is engaged in a theft scheme, leading to a climactic arrest drama.
Interspersed among other incidents are scenes of Tokyo in the near future, when the city suffers from economic paralysis due to hyperinflation. Has Riko's gifted eye discerned the makings of an international plot that could alter Japan's future? This mystery carries over into volume two of the series.
Following the twelve volumes of the Case Files series, an additional eight volumes featuring Riko have appeared as of February, 2014, with combined sales of over four million books. A live-action film based on the series is slated for release in May 2014.