Question

I've been reading alot of harada lately and I've recalled a manga that I read quite some time ago. I dont know the same since I wasnt on mangago at the time.

It's about these two kids (ages 4-6?) One from a wealthy family. Let's call him blondie. And the other one was normal, timid and very very shy. Hes blackie. One day an old man comes up to blondie and tells him that he is pretty and asks if he would like to come with him. Blondie, the genius gets the weird vibes and tells him that he isnt pretty. And he points to blackie and says he is prettier the old man looks and agrees, taking blackie with him. The boy disappears. Flash forward to I think 15-20 years later and blondie gets kidnapped. He doesnt know this guy, but he is oddly familiar. Turns out blackie had been imprisoned the entire time and was freed after the old man died. Please help me look for it!!! I would be ever so grateful!