In the book Everyday, by David Levithan, 'A', the main character, wakes up in a new body everyday of his life. Every morning he has to wake up and find out who he is. This isn't very hard for him. He then has to be that person for one day.
One day he wakes up as Justin. Justin has a girlfriend named Rhiannon. A falls in love with her. Even when he is someone else, someone 4 hours away from her, he still loves her. A does everything in his power to be with her. He uses Justin's email the day he lives as him. He knows his password and has access to all of his emails. They meet up whenever they can. Eventually A tells Rhiannon the truth about how he lives. At first she doesn't know weather to believe him or not. She tells him to come back and meet her again tomorrow so she can see that he will be a different person. She then believes him.
One morning, A woke up as Nathan Daldry. He finds out he is only 90 minutes away from Rhiannon. He also uses Justin email to find out that there is a party at Steve Masons house. Nathan goes to the party to see Rhiannon. She has no idea who's body A is in today. Nathan shows up to the party and finds her. he starts to talk to her. When Nathan is talking to Rhiannon, Justin happens to stop by. Justin gets a little mad but then Nathan made up an excuse of why he was there and who he was. Later, Nathan and Rhiannon were dancing in the basement. Nathan realized the time and needed to get home. midnight was not only Nathans curfew. Its when A changes into a different body. A falls asleep on the way back to Nathans house in his car on the side of the road.
The next morning on the news there is a story about a boy being taken over by the devil. Sure enough, it was Nathan. A couldn't change anything now. A few days passed and the story kept growing. It was on the news more often and more people were worried about it. Nathan now has Justin's email address because A logged into it on Nathans computer. Nathan begins emailing A and doesn't stop until he gets an answer. A doesn't answer him at first, but Nathan keeps emailing him. Eventually A answers Nathan.
After a few weeks of emailing, A decides to meet up with Nathan and tell him everything. Nathan believes him but he wants to see proof that A is a new person everyday. Nathan asks A to come over the next day. He does and he is a new person. Nathan is surprised that he really is a new person everyday. At Nathans house he meets Reverend Poole, a publisher of a website about the devils presence. A is worried at first and tries to leave but he is stopped. Reverend Poole talks to him about how he lives. He asks if A sees any connection with the devil. A says no. Reverend Poole keeps asking all these questions and A keeps disagreeing. Reverend Poole eventually says that there is another 'person' like A and that A could stay in someone's body longer than a day if he learned how to control it. A doesn't want to believe him but after he leaves Nathans house, those words stick with him. He keeps thinking about what he said. He tries to control it by inviting Rhiannon to a boys house. He tells her that he will remember that night even when A isn't with him. The next day A wakes up in a new body and decides to run.