The Time Keeper - Mitch Albom

Banished for centuries, as punishment for trying to measure time, the inventor of the world’s first clock is finally granted his freedom, along with a mission: a chance to redeem himself by teaching two people the true meaning of time.

He returns to our world and embarks on a journey with two unlikely partners: a teenage girl who is about to give up on life and a wealthy, ageing businessman who wants to live for ever. To save himself, he must save them both.