The titular Jack is Jack Horner AKA Jack the Giant Killer, Jack Frost and several other Jacks of legend and lore. And Jack is in a world of trouble. He's been kidnapped and is imprisoned at the Golden Boughs Retirement Community, which is where Fables (those animals and people from folk and fairy tales living among us) who are too dangerous or undesirable are sent to live ouit their days. The place is run by the mysterious Revise and his librarians the Page sisters.
It's kind of like The Brothers Grimm meet The Prisoner. And it's a lot of fun. I especially appreciated seeing an old friend from my days of having books read to me. I won't say who he is, but he has the awesome power to turn tigers into butter