The narrative arc of this gripping mystery is not simple and you do have to pay attention. But that's true to the source material of the novel. Moreover, the point of the story has more to do with complex issues of truth, social stratification, and the search for safety from trauma, than your garden-variety murder mystery usually serves up. Furthermore, the back-and-forth pattern of the storytelling emphasizes the reality of cataclysmic personal trauma: one can never really leave the terrible event in the past. To watch good people self-destruct under the weight of their own bad choices can be intensely moving, but that's why real tragedy has been a staple of great drama for thousands of years. Don't be afraid to give yourself the gift of seeing great actors in a terrible ordeal just because you might have to pay close attention to the time-shifting plot.
