Ren Ishida has nearly completed his graduate degree at Keio University when he receives news of his sister's violent death. Keiko was stabbed one rainy night on her way home, and there are no leads. Ren heads to Akakawa to conclude his sister's affairs, failing to understand why she chose to turn her back on the family and Tokyo for this desolate place years ago. But then Ren is offered Keiko's newly vacant teaching position at a prestigious local cram school and her bizarre former arrangement of free lodging at a wealthy politician's mansion in exchange for reading to the man's ailing wife. He accepts both, abandoning Tokyo and his crumbling relationship there in order to better understand his sister's life and what took place the night of her death.
As Ren comes to know the eccentric local figures, from the enigmatic politician who's boarding him to his fellow teachers and a rebellious, captivating young female student, he delves into his shared childhood with Keiko and what followed. Haunted in his dreams by a young girl who is desperately trying to tell him something, Ren realizes that Keiko Ishida kept many secrets, even from him.