Which drama is this?

I watched this drama a couple months ago about this guy’s brother got kidnapped on a rainy day and when he comes back he acts normal around his family but he does strange stuff at night like he goes out to dangerous places and it’s like he’s in some sort of gang. But in the end we find out that the main character is actually this older man whos being accused of killing this family. I can’t remember the name of it or find it anywhere. 

I second the movie Forgotten! Really good, you should check it out.