A Monster Calls is the emotional story of Connor, as he comes to grips with his mother's impending death. A Monster in the form of a giant yew tree begins to visit him (in reality or in his imagination is left to the reader to decide), telling Connor that he has come because Connor called him and is there to help.
Ness writes wonderfully, and is an excellent storyteller. Even when I wasn't enjoying the story, I was captivated by both the tale and the prose. The character of the Monster was fantastic, wild and gentle at the same time. I also liked how Ness slowly revealed parts of Connor's life, giving hints for the reader along the way.
I had mixed feelings about this novel. On the one hand, it is an excellent depiction of grief, and of the unraveling of reality and emotions during a time of extreme stress. Furthermore, it encourages the reader that it is okay to be angry about situations like this, and shows that fairy tale happy endings don't come about when dealing with terminal illness.
On the other hand, I didn't feel that Connor or the Monster gave the best example or advice for dealing with grief. The monster is encouraging Connor to act during two episodes when Connor has a mental breakdown and becomes violent. Encouraging as in urging him on to more destructive actions. In addition, this extreme damage to both a person and some property is glossed over, never fully addressed. "What good would it do?" is the reaction of the adults in his life. I felt that this was an unhealthy message to present to the target reader.
Granted, this is just my opinion: Patrick Ness won the Carnegie Medal for A Monster Calls, so other responsible adults feel that the lessons being taught are appropriate.