Not all stories begin at the beginning. Some start with a grin. Thirteen grins, to be exact. To grin (like a Cheshire cat) means to smile broadly. Some definitions of the term stipulate that the smile must be so broad as to expose the gums. The idiom "grin like a Cheshire cat" may have the connotation that the person who is grinning is in possession of knowledge that the beholder is not aware of. And that is precisely what makes the grins so exciting - you never know what comes next. Even though it was already there, right in front of your eyes.