Yuushi Kamome is a freelance journalist who lost his beloved daughter in an unforeseen accident. His descent into despair following her death drove his wife to leave him, and he lives each day a shell of the man he once was.

But his fate changes one day when members from a religious organisation he had never heard of, the Smiling Hearts Society, knock on his door and hand him a flyer. He's ready to dismiss them until he notices the face of his estranged wife on the flyer, smiling ever so softly.

And so begins a tale of religion and insanity. What kind of sinister darkness lurks behind this religion and its strange smiles?