The novel was very captivating. I got absorbed right from the first volume. IT always keeps you guessing answers to questions like "Who is it?" "Why is he/she doing this?" "How could you possibly escape from this situation?" and so on. I know that seems like typical of mystery/thriller genre. But there is a difference. Many anime (I cant speak of many novels/manga as I haven't read that lot) may confuse you but it is rare for me to invest myself thoroughly in a series and put myself in the Protagonist's shoes and think through stuff. Only few have managed to absorb me that much. This is one of them.

The novel is not all about thriller or mystery. It also deals with topics like human nature through its (quite eccentric) characters. While some stay true to their ideals and nature throughout the series like Maria, whereas, others grow out of their comfort-zone like Kazuki. And, this does not happen in a sudden fashion. It happens gradually and beautifully.

Talking about characters, to be honest some are realistic but few like Maria are far from it. Even though I liked her, you see few people like her. But, every character was well written with some level of background and depth. You will come to like some and hate some.

Another reason why I loved the novel -- I am a sucker for romance, and this novel delivered it. It is light at the beginning. But towards the end you have quite intense drama and romance involved.

The last reason would be its ending. This is where most anime I have watched fail. This had a good conclusion. Even to romance. Even though, I wanted more of the novel, I was satisfied with the way it ended.