Basically the same exact plot. The father of the main lead writes in his will that he gives all of his inheritance to the poor female lead (daughter of his first love) and the male lead can only share if he marries her so he tries to seduce her to take the inheritance but falls in love with her

These dramas are very similar. Both are in a class society. Both have mystery deaths. In both, the dead may not be dead after all. Lots of secrets and crazy plot twists to be revealed in both. In both, the female lead has a love interest with a mysterious man under a hidden identity that will help them a lot in revenge and fall in love.

Both dramas are based on a high society, from what I noticed- Show Window: The Queen's House is less focused on academics as The Penthouse but both dramas are focused on stepping over others and cheating to become the richest and top in the society. In the Penthouse, everyone is obviously neighboring in the penthouse with people who will turn on you anytime for social gain, in the Show Window: The Queen's House- they neighbor in a "rich society only neighborhood." In both dramas, there will be a mystry murder that happens in the very end but is also the opening of the drama in the first episode as a flashback which keeps us guessing who the murdered person is and who the murderer is. In both, the wife is nice to the mistress, but that doesn't stop the mistress from being jealous anyways and doing anything to ruin the wife and steal her riches. In both, the husbands are trash and are only married to the wives to steal their riches and company. Very similar vibes. If you enjoyed The Penthouse, you'll definitely enjoy this.

In both dramas, the husband will be married to a woman and also have a mistress, he'll pretend to be devoted to both. The mistresses in both dramas will approach the wife and pretend to be friends with them. In both, there will be a mystery murder. The vibes and society are also very similar. If you liked high class, you will like Show Window: The Queen's House