I understand this is the writer's first published work. On that note, it's quite impressive for a first try. The story itself revolves around a character named Edgar, who recounts in the first person various events through stages of his life. A mix of good events and bad events (foolish mistakes Edgar makes) are recalled throughout the story.
Due to the juxtaposition of the good and the bad, there's a constant shift in the mood of the readers. One moment, you feel warm and glad over some of the good things that the narrator does. Other times, you slap your forehead in frustration when he does something incredibly foolish. I did this myself whenever Edgar did something dumb and when I got to the last part of the book, I openly said aloud "You have got to be kidding me!" This is the FIRST time I've done either of these things in a long time when I was reading literature. Yes, the writing was that powerful.
The Seventh Sin is a hidden gem and is worth picking up.