For the two romantic leads in  “One Day,” getting to know each other in 20 years proves to be difficult, but for the audience it’s nearly impossible.

In this romantic comedy, Emma Morley (Anne Hathaway) and Dexter Mayhew (Jim Sturgess) become best friends July 15, 1988, the night of their graduation from college. From there, the film, like the novel it’s based on, skips ahead to revisit the graduates on the same summer day for the next 20 years of their lives. During that time, Dexter becomes a celebrity television host and falls into heavy drug and alcohol use, while Emma struggles to find her own career.

The highly anticipated film serves more as an outline of the book as it simply skims the surface of Dexter and Emma’s lives. In adapting his own work, Nicholls isn’t quite successful at making Dexter and Emma’s romance a believable one. What was a sincere novel about friendship and the reality of youthful aspiration has been reduced to merely shallow sentiment.

In the film, Dexter’s honest attempt at getting to know Emma the night they meet makes up for his otherwise irritatingly selfish schoolboy personality. But as he grows up, he becomes as much of a wreck as he is in the novel and his new celebrity persona makes it harder to root for him. Sturgess’ character is so extremely unlikable on-screen; it’s nearly impossible to believe Emma would ever fall in love with his narcissistic attitude.

On the page, Emma is filled with awkward insecurities but is more intelligent and wittier than she appears. Hathaway, who slips in and out of a fake British accent, understands the character she’s playing but can’t fully become Emma Morely, due to Nicholls’ thin screenplay that flies over the most important moments of her life.

The shocking, tragic twist that comes in the final act gives the story more sentiment than it deserves, mainly because it’s manipulatively foreshadowed in the first scene of the movie. Though their romance isn’t a truly plausible one, Sturgess and Hathaway share some chemistry together in their later years. A few grand moments of feeling give readers a glimpse of the smarter film it could have been.

Despite the best efforts of the cast, “One Day” trades its unusual premise for an unsatisfying romance, which makes it difficult to spend even one day with the characters.

“One Day” was written by David Nicholls and directed by Lone Scherfig.

2 out of 4 stars