Each time Harry August dies he is reborn in his same life at his birth. Harry gets to relive his life endlessly with the benefit of remembering everything and being able to change his life each time. He is not the only one. There are a few others like him and they belong to the Cronus Club where they help each other, but there is one rule.
They are not allowed to change the world drastically and the punishment could be permanent death. Harry and the members of the Cronus Club can be destroyed if they are not allowed to be born. Harry has nothing to worry about until he gets a message from the future that the world is ending.
In The First Fifteen Lives of Harry August by Clare North, Harry has to choose between living without a care or to try and stop the world from ending and possibly make an enemy who would destroy him forever.