Will You Be There?

Su Hyeon comes across magical pills that allow him to go back and forth in time. 30 years earlier, a young Su Hyeon meets his future self and learns that his girlfriend will soon die because of him. In order to save her, the two Su Hyeons try to change the past, but a completely new and unexpected past is formed, which leads to a new future.
(Source: KoBiz)
~~ Adapted from the novel "Will You Be There?" (Seras-tu là ?) by Guillaume Musso.