This film is so confused, contrived, messy and improbable, that there is no evidence of anyone's having thought their way through the contradictions that riddle any time-travel plot. Credibility having been abandoned,there is really nothing left to hold the viewer. It is not possible to believe that these characters believe any of this junk, and the viewer's mind simply wanders off. A mess. If one compares it with equally fantastic premises in films that actually work, the exercise is rewarding. I would suggest one from more than sixty years ago, entitle A Matter of Life and Death (also released as Stairway to Heaven) by The Archers, and starring David Niven and Kim Hunter: a great sense of play, and a careful adherence to the premises.