A moment. An exchange. A heart that will never be the same again. Allie does not believe in great love, she prefers to analyze it with scientific precision. When she returns to Manchester exhausted after a long research project, she finds herself on the flight next to none other than Milo Ford, the charming film star and walking epitome of romance. When they arrive at their destination, they both realize that they have swapped their cell phones. A disaster, because their careers depend on being available at all times. Without further ado, they decide to take over each other's digital lives until they can exchange back - because Milo is in the Romanian mountains, without a courier service, without a chance to meet for the next seventy days. But as they navigate unfamiliar news, intimate insights, and unexpected revelations, a bond grows that neither of them sees coming...