The last Missing Piece of the tv-serie Lost is starred by John Terry and Matthew Fox, who play the roles of Christian and Jack Shepherd. It also features Madison, which is Vincent, Walt's dog.
The story begins when Vincent the Dog is walking through the island, and then somebody calls him. It's Christian Shepherd, who whispers "Go and find my son". Then Jack opens the eyes, as he did at the beginning of the serie, and looks to her left. There's Vincent, of course. So you assume this is someting that happens just after the plane crash; but before Jack wakes up (if you remember, the Jack's waking up is the first scene of Lost); and if Vincent was there when Jack waked up it was because Christian Shepherd (or whoever he is now) told the dog to do it. And, as the title of this Mobisode says, so it begins.