Tia

The FL is ruthless and will do anything to get to and stay at the top. Both FLs are ruthless and extremely manipulative, as well as cold-hearted. Most of the characters in both shows are morally grey.

There's a large group of villains against one heroine. And none of them feel sorry- at all. But the heroine may become an anti-heroine, similar to Go Eun-Jo/Hwang Ga-Heun. Stella Jang is also similar to Hwang Ji-Na. Seol-Hee/Lucia also lost her child like Eun-Jo/Ga-Hun because of the villains.

Many of the main/major characters are similar to the ones in The Penthouse. Even the general plot is similar to Season 1's plot of The Penthouse. For example, a daughter dying and the mother setting out to avenge the ones behind her death and find the killer. The only difference is that Shim Su-Ryeon is more of a morally grey character (and so is Oh Yoon-Hee) and Su-Ryeon is rich and married to a businessman, while Baek Seol-Hee is a poor, hardworking single mother.