Wren Wheeler has flown five thousand miles across the ocean to discover she's the worst kind of traveller: the kind who just wants to go home. Her senior-year trip to London was supposed to be life-changing, but by the last day, Wren's perfectly-planned itinerary is in tatters. There's only one item left to check off: breakfast at The World's End restaurant.
The restaurant is closed for renovations-of course-but there's a boy there, too. A very cute boy with a posh British accent who looks remarkably like the errant Prince Theo, on the run from the palace and his controlling mother. When Wren helps the Prince escape a pack of tourists, he offers her one favour in return. She doesn't plan to take him up on it-until she gets to the airport and sees cancelled flights and chaos. A comet is approaching Earth, and the world is ending in eight days. That favour could be her only chance to get home.
Wren strikes a bargain with the runaway prince: if she'll be his bodyguard from London to his family's compound in Santorini, he will charter her a private jet home. As they travel through Europe by boat, train, and accidentally stolen automobile, Wren finds herself drawn to the dryly sarcastic, surprisingly vulnerable Theo. But the Prince has his own agenda, one that could derail both their plans.
