These two concerns with knowing about your own future and trying to choose a path in present that makes a better future. During TOMORROW WITH YOU the male lead travels to the future and simply witness something he wants to avoid. He then comes back and try his best to change his future. During ORANGE the leads from the future send letters to their own present version and warn them of the unpleasant incidents of the time, so these incidents could be avoided.
Both series have the vibes interms of interactions between leads. HIDDEN LOVE features cute moments, giggles and light hearted conversation between leads through the time( both past story line and today). STARTUP THE ENGINE shows those moments in a limited way and only for the leads romantic relationship. The vibes, theme, jokes and feelings if the scenes are the same in both
These are stories with reincarnation of drama characters involved in a romantic relationship. In "See You in My 19th Life " the female lead is born again and searched for his previous life important person who becomes his romantic interest in current life. In "To all the Guys Who Loved Me" the leads had an unfortunate relation in previous life and a lot of incidents happened that male lead felt should be corrected. So in both dramas one of the leads used a past life information to built a better current life
