After graduating from Watford, Simon and Baz and their friends are out in the real world and feeling a bit stuck. Simon has lost his magic and his sense of purpose in the world, and Baz is just well worried because Simon hasn't gotten off the couch in weeks. Penelope comes up with the perfect plan to lift them out of their doldrums--a trip to America to visit Micah and Agatha. Of course nothing goes as planned once they get there. What starts out as a simple vacation in the States turns into a high-stakes cross country road trip where the survival of humanity as we know it just might rest in these wizards' hands.