Suddenly She's Here

Everything was going just fine for Oscar until one day when he woke up to find a girl in his room. Her name is Mika and she claims to have known him and his family for a long time. However, Oscar doesn't recognize her at all but to make things even more confusing, everyone around him is acting like she's always been around! As he spends more time with her, he will uncover the mystery of who she really is, assuming he doesn't try to run away from all of this. Just who is this girl and why is she messing is his life up?