The premise is so similar that one may think Ugly Alert is inspired from Happy together. There are some differences in story but a lot more similarities. The OSTs are also good in both dramas.
Both about step siblings,
in both- the father is a thug,
in both- parents die and siblings from the mothers side blame the step father,
in both- prosecutor younger brother
in both- both brothers like the same girl at one point
in both- the father is a thug,
in both- parents die and siblings from the mothers side blame the step father,
in both- prosecutor younger brother
in both- both brothers like the same girl at one point