Both are about someone reliving the same day over and over and trying to save the life of another person who always dies that day.

Both are movies about two isolated troubled young people - a rougher but good-hearted guy and a depressed girl - who bond and struggle to overcome the difficulties of their lives. While both have a tragic tone, BD has a much happier ending.

Both are about a rich ML and poor FL couple that break up and the FL returns years later with her young son. The ML discovers later on that she was pregnant when they broke up and the child is his.

Both are a similar story in which a married couple breaks up due to scheming from family/other women, and the FL returns a few years later, stronger, and with a plot for revenge. In both, the FL had a baby but the plot in gender--flipped (in PL she secretly raised him and the ML believes she had an abortion, in MC the ML raised him and the FL believes he died at birth).

Both are about a married couple that break up after scheming from multiple people including a woman who wants the ML for herself. The FL returns a few years later with her young child who the ML later discovers is his son.

Both are about a married couple that breaks up due to scheming from family/another woman, and the FL returns for revenge five-six years later. The ML soon discovers she was pregnant when they broke up and he has a young child.

Both are about the relationship between a rich man and poorer woman which bitterly breaks up. Five-six years later, the two cross paths again and begin living together, and the ML discovers he has a young child he didn't know existed.

Both are about a rich ML and poorer FL who were in love but separated due to scheming from the ML's family/friends. The two reunite when the FL returns 5-6 years later. The ML later discovers the FL was pregnant when they broke up and he now has a young child who he interacts with before realizing the child is the FL's or his. Both have an identical scene where the ML sees the FL working at a nightclub and misunderstands her.

Both are different variations of the same story and concept.
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Both are different variations of the same story and concept.
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Season 2 is the prequel/backstory to season 1.
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Same leads in both mini dramas, but a different plot.
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