Nobody Knows(2011)

The “self bully” Ban has a normal enough life, and where divorced parents aren’t that uncommon, her life becomes shadowed in mystery when her mother, Eun-Joo, suddenly brings their “distant relative” Jin-Whan home to live with them. Ban’s mother would always avoid the topic of her family, so who is this strange boy? Are they really relatives? What torturous secrets does her mother’s past hold? And what do the sudden strange happens that follow in Jin-Whan’s wake mean? Would a better question not be who is he, but what?