Complex sentence: Each time the hour resets, Myron retains his memory (or as the film puts it, his consciousness), and despite his best attempts to understand what is happening, he ultimately realizes that he is entirely helpless to prevent the time bounce.
Split into simpler sentences: Each time the hour resets, Myron retains his memory (or as the film puts it, his consciousness). Despite his best attempts to understand what is happening, he ultimately realizes that he is entirely helpless to prevent the time bounce.