You Are Not Alone

After his death, Tadashi became a ghost whose sole purpose is to protect Hiro and follow him wherever he goes, keeping him out of trouble. Hiro is having strange feelings like someone is there with him but he can't see anyone. Soon, he starts seeing the ghost of his brother and tries to adjust. Hiro realizes that he's not alone, and he never was. Tadashi was here, and now he knows.