Nutshell“Nutshell,” Ian McEwan’s preposterously weird little novel, is more brilliant than it has any right to be. The plot sounds like something sprung from a drunken round of literary Mad Libs: a crime of passion based on Shakespeare’s “Hamlet,” narrated by a fetus. That it should come to this! If you can get beyond that icky premise, you’ll discover a novel that sounds like a lark but offers a story that’s surprisingly suspenseful, dazzlingly clever and gravely profound.