A Monster Calls is a fantasy drama about a young boy whose life is crap, basically. His mother is sick. His father has scarpered. He is being bullied at school. He may also have an itch he can’t get at, for all we know. (Always hateful, that.) But he finds an ally when the ancient yew tree he can see from his window morphs into the giant tree monster who’ll take him on a journey of ‘courage, faith and truth’.