The dynamic is also very well measured. All in good time, history is never too fast, not too slowly, so that you can fully appreciate this story, from the first to the last line! As for the story itself, it is excellent! Kayla being back in different periods of its past to improve its future, it was an absolutely gigantic idea! I admit particular have enjoyed the passage where it was found in his body 10 years old! What imagination!
As for the end, I found it very appropriate, suggesting at all that everyone is master of his fate, he just have to want to get there, or just have people who love you to give you a little help inch is needed at the right time!