Violet, Klaus, and Sunny Baudelaire are the three unfortunate main characters of Snicket's books - a series which is aptly titled: "A Series of Unfortunate Events". The Baudelaire children have just been orphaned and it's up to the incomptetant Mr. Poe to find them an appropriate guardian.
But instead they are left in the hands of Count Olaf, a repulsive villain who plots to steal their fortune.