Since his 18th birthday, Woo-jin has awoken each morning as a different person. His age, gender, even race can change. He has no way of controlling it and there is no known cure. Now almost 30, Woo-jin lives alone designing custom-made furniture. Only his mother and best friend are aware of his affliction.

 When he meets the beautiful Yi-soo (played by Han Hyo-joo), Woo-jin is smitten. Waiting until he is young and handsome to make his move, he resolves to stay awake as long as possible, leading to a blissful two-day courtship. But how long can he keep this up?

 Inspired by a 2012 American “social film” conceived by Intel and Toshiba, the high-concept premise offers plenty of comedic potential, not to mention questions about gender and sexual orientation, racism and ageism, but this South Korean adaptation plays things straight and frustratingly safe.

As Woo-jin is portrayed by a different actor in every scene (which leads to numerous big-name cameos), the film’s heavy lifting falls to Han, as her character struggles to love someone who can be a different person each day. The actress does good work throughout, despite a script that repeatedly favours melodramatic soul-searching over more serious and pressing issues.