It's the fourth SineSerye and for this season it's Lino Brocka's "Natutulog ba ang Diyos?"
Everyone notices how different Andrew (Jake Cuenca) and Gillian (Roxanne Guinoo) looked from their respective sets of parents but no one really made a fuss about it. What is even more surprising is that the two never felt close with the families they grew up with. Instead, Gillian became more attached with Andrew's parents (Matt Ranillo III and Lorna Tolentino) and Andrew felt the same about Gillian's parents (Ronnie Lazaro and Rosanna Roces). Little did they suspect that it was because Andrew and Gillian were switched at birth. Andrew's real father (Ronnie Lazaro) a poor family driver decided that Andrew would have a better life growing up with his rich bosses. So he made sure that only he and his wife Gina know that he switched babies when the two mothers gave birth at a provincial hospital. No amount of pleading from Gina would make him change his mind. Out of frustration, Gina resorted to maltreating Gillian. The latter found comfronting arms in Marita, Andrew's mother. And later on with Mark (Joross Gamboa) a rich suitor. Jealous at Gillian's new found attention. Andrew decided to force himself on Gillian. An act which would lead to revelation of the secret of their parentage. On the other hand, Mark (Joross Gamboa), who adds to the confusion, as he's Andrew's best friend, who also has feelings for the same girl.
Plot taken from Wikipedia.