The film starts with the murder of a teenage girl, who is the daughter of counter-terrorism officer in LA just after 9/11 working with a partner. Both are devastated by the murder. 13 years later, he feels he's tracked down the main suspect.
The story issue for having a dual time line is there needs to be dramatic tension and a clarity of purpose combining story and plot on both time lines. There needs to be an underlying, single story line.
The plot line and plot question is always clear, will the main character track down the murderer after 13 years. But the story is more complicated and that underlying story question that connects both plot line and both story lines felt diffuse. The film is about loss and obsession and not being able to let go of the 'what if' moments in life that define the characters. But the issue of 'what if' moment around a romantic attraction never quite connects to a story line.
A complicated plot like this creates what I call a traffic cop effect, with scenes organized around what needs to happen for the plots on both time lines to work and build to that big reveal. The director and actors pull off the plot and I admire how the characters are portrayed, but a deeper level of psychological depth never developed on the story line. Without that, scenes felt superficial, typical Hollywood-thriller scenes.
Interesting film, an attempt to get at something deeper. That requires a clear vision of the story and a sense of purpose from everyone involved.