Right to the point:
The happy couple, not long married, are out for a pleasant evening. They're hit by a truck. He recovers. She forgets him and their life. The rest is his struggle to win her love again, while others take advantage to turn her history the way it didn't go the first time.
A pleasant date movie, this story is well done, enjoyable, and predictable. And turns out it's true.
What to do when she forgets the last five years, returns to the past, and heads down the path everyone thought she would the first time? Why didn't she continue that way the first time? What could possibly persuade her to change course - again - the same improbable way? Intriguing questions with compelling answers.
How he could, should, and does handle this agonizing rewind is thought provoking. She is his wife, he is an utter stranger, and the pursuit & avoidance of intimacies amid trust and lack thereof makes for aching drama. The proof of their past is irrefutable, but the compulsion to repeat it is a mystery.
Methinks this movie is underrated. It excels at its goal at the exclusion of the wow-bang-shiny we're so used to, making it look so easy we miss the profundity of the human drama it tells.